WorldWideScience

Sample records for charge state coronal

  1. Coronal seismology waves and oscillations in stellar coronae

    CERN Document Server

    Stepanov, Alexander; Nakariakov, Valery M

    2012-01-01

    This concise and systematic account of the current state of this new branch of astrophysics presents the theoretical foundations of plasma astrophysics, magneto-hydrodynamics and coronal magnetic structures, taking into account the full range of available observation techniques -- from radio to gamma. The book discusses stellar loops during flare energy releases, MHD waves and oscillations, plasma instabilities and heating and charged particle acceleration. Current trends and developments in MHD seismology of solar and stellar coronal plasma systems are also covered, while recent p

  2. Charge States of Krypton and Xenon in the Solar Wind

    Science.gov (United States)

    Bochsler, Peter; Fludra, Andrzej; Giunta, Alessandra

    2017-09-01

    We calculate charge state distributions of Kr and Xe in a model for two different types of solar wind using the effective ionization and recombination rates provided from the OPEN_ADAS data base. The charge states of heavy elements in the solar wind are essential for estimating the efficiency of Coulomb drag in the inner corona. We find that xenon ions experience particularly low Coulomb drag from protons in the inner corona, comparable to the notoriously weak drag of protons on helium ions. It has been found long ago that helium in the solar wind can be strongly depleted near interplanetary current sheets, whereas coronal mass ejecta are sometimes strongly enriched in helium. We argue that if the extraordinary variability of the helium abundance in the solar wind is due to inefficient Coulomb drag, the xenon abundance must vary strongly. In fact, a secular decrease of the solar wind xenon abundance relative to the other heavier noble gases (Ne, Ar, Kr) has been postulated based on a comparison of noble gases in recently irradiated and ancient samples of ilmenite in the lunar regolith. We conclude that decreasing solar activity and decreasing frequency of coronal mass ejections over the solar lifetime might be responsible for a secularly decreasing abundance of xenon in the solar wind.

  3. SUPRATHERMAL ELECTRONS IN THE SOLAR CORONA: CAN NONLOCAL TRANSPORT EXPLAIN HELIOSPHERIC CHARGE STATES?

    International Nuclear Information System (INIS)

    Cranmer, Steven R.

    2014-01-01

    There have been several ideas proposed to explain how the Sun's corona is heated and how the solar wind is accelerated. Some models assume that open magnetic field lines are heated by Alfvén waves driven by photospheric motions and dissipated after undergoing a turbulent cascade. Other models posit that much of the solar wind's mass and energy is injected via magnetic reconnection from closed coronal loops. The latter idea is motivated by observations of reconnecting jets and also by similarities of ion composition between closed loops and the slow wind. Wave/turbulence models have also succeeded in reproducing observed trends in ion composition signatures versus wind speed. However, the absolute values of the charge-state ratios predicted by those models tended to be too low in comparison with observations. This Letter refines these predictions by taking better account of weak Coulomb collisions for coronal electrons, whose thermodynamic properties determine the ion charge states in the low corona. A perturbative description of nonlocal electron transport is applied to an existing set of wave/turbulence models. The resulting electron velocity distributions in the low corona exhibit mild suprathermal tails characterized by ''kappa'' exponents between 10 and 25. These suprathermal electrons are found to be sufficiently energetic to enhance the charge states of oxygen ions, while maintaining the same relative trend with wind speed that was found when the distribution was assumed to be Maxwellian. The updated wave/turbulence models are in excellent agreement with solar wind ion composition measurements

  4. q-deformed charged fermion coherent states and SU(3) charged, Hyper-charged fermion coherent states

    International Nuclear Information System (INIS)

    Hao Sanru; Li Guanghua; Long Junyan

    1994-01-01

    By virtue of the algebra of the q-deformed fermion oscillators, the q-deformed charged fermion coherent states and SU(3) charged, hyper-charged fermion coherent states are discussed. The explicit forms of the two kinds of coherent states mentioned above are obtained by making use of the completeness of base vectors in the q-fermion Fock space. By comparing the q-deformed results with the ordinary results, it is found that the q-deformed charged fermion coherent states and SU(3) charged, hyper-charged fermion coherent states are automatically reduced to the ordinary charged fermion coherent states and SU(3) charged hyper-charged fermion coherent states if the deformed parameter q→1

  5. Charge state evolution in the solar wind. III. Model comparison with observations

    Energy Technology Data Exchange (ETDEWEB)

    Landi, E.; Oran, R.; Lepri, S. T.; Zurbuchen, T. H.; Fisk, L. A.; Van der Holst, B. [Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, MI 48109 (United States)

    2014-08-01

    We test three theoretical models of the fast solar wind with a set of remote sensing observations and in-situ measurements taken during the minimum of solar cycle 23. First, the model electron density and temperature are compared to SOHO/SUMER spectroscopic measurements. Second, the model electron density, temperature, and wind speed are used to predict the charge state evolution of the wind plasma from the source regions to the freeze-in point. Frozen-in charge states are compared with Ulysses/SWICS measurements at 1 AU, while charge states close to the Sun are combined with the CHIANTI spectral code to calculate the intensities of selected spectral lines, to be compared with SOHO/SUMER observations in the north polar coronal hole. We find that none of the theoretical models are able to completely reproduce all observations; namely, all of them underestimate the charge state distribution of the solar wind everywhere, although the levels of disagreement vary from model to model. We discuss possible causes of the disagreement, namely, uncertainties in the calculation of the charge state evolution and of line intensities, in the atomic data, and in the assumptions on the wind plasma conditions. Last, we discuss the scenario where the wind is accelerated from a region located in the solar corona rather than in the chromosphere as assumed in the three theoretical models, and find that a wind originating from the corona is in much closer agreement with observations.

  6. Charge state evolution in the solar wind. III. Model comparison with observations

    International Nuclear Information System (INIS)

    Landi, E.; Oran, R.; Lepri, S. T.; Zurbuchen, T. H.; Fisk, L. A.; Van der Holst, B.

    2014-01-01

    We test three theoretical models of the fast solar wind with a set of remote sensing observations and in-situ measurements taken during the minimum of solar cycle 23. First, the model electron density and temperature are compared to SOHO/SUMER spectroscopic measurements. Second, the model electron density, temperature, and wind speed are used to predict the charge state evolution of the wind plasma from the source regions to the freeze-in point. Frozen-in charge states are compared with Ulysses/SWICS measurements at 1 AU, while charge states close to the Sun are combined with the CHIANTI spectral code to calculate the intensities of selected spectral lines, to be compared with SOHO/SUMER observations in the north polar coronal hole. We find that none of the theoretical models are able to completely reproduce all observations; namely, all of them underestimate the charge state distribution of the solar wind everywhere, although the levels of disagreement vary from model to model. We discuss possible causes of the disagreement, namely, uncertainties in the calculation of the charge state evolution and of line intensities, in the atomic data, and in the assumptions on the wind plasma conditions. Last, we discuss the scenario where the wind is accelerated from a region located in the solar corona rather than in the chromosphere as assumed in the three theoretical models, and find that a wind originating from the corona is in much closer agreement with observations.

  7. CORONAL SOURCES, ELEMENTAL FRACTIONATION, AND RELEASE MECHANISMS OF HEAVY ION DROPOUTS IN THE SOLAR WIND

    Energy Technology Data Exchange (ETDEWEB)

    Weberg, Micah J. [PhD Candidate in Space Science, Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, 2134A Space Research Building, 2455 Hayward Street, Ann Arbor, MI 48109-2143, USA. (United States); Lepri, Susan T. [Associate Professor, Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, 2429 Space Research Building, 2455 Hayward Street, Ann Arbor, MI 48109-2143, USA. (United States); Zurbuchen, Thomas H., E-mail: mjweberg@umich.edu, E-mail: slepri@umich.edu, E-mail: thomasz@umich.edu [Professor, Space Science and Aerospace Engineering, Associate Dean for Entrepreneurship Senior Counselor of Entrepreneurship Education, Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, 2431 Space Research Building, 2455 Hayward Street, Ann Arbor, MI 48109-2143, USA. (United States)

    2015-03-10

    The elemental abundances of heavy ions (masses larger than He) in the solar wind provide information about physical processes occurring in the corona. Additionally, the charge state distributions of these heavy ions are sensitive to the temperature profiles of their respective source regions in the corona. Heavy ion dropouts are a relatively new class of solar wind events identified by both elemental and ionic charge state distributions. We have shown that their origins lie in large, closed coronal loops where processes such as gravitational settling dominate and can cause a mass-dependent fractionation pattern. In this study we consider and attempt to answer three fundamental questions concerning heavy ion dropouts: (1) 'where are the source loops located in the large-scale corona?'; (2) 'how does the interplay between coronal processes influence the end elemental abundances?'; and (3) 'what are the most probable release mechanisms'? We begin by analyzing the temporal and spatial variability of heavy ion dropouts and their correlation with heliospheric plasma and magnetic structures. Next we investigate the ordering of the elements inside dropouts with respect to mass, ionic charge state, and first ionization potential. Finally, we discuss these results in the context of the prevailing solar wind theories and the processes they posit that may be responsible for the release of coronal plasma into interplanetary space.

  8. CORONAL SOURCES, ELEMENTAL FRACTIONATION, AND RELEASE MECHANISMS OF HEAVY ION DROPOUTS IN THE SOLAR WIND

    International Nuclear Information System (INIS)

    Weberg, Micah J.; Lepri, Susan T.; Zurbuchen, Thomas H.

    2015-01-01

    The elemental abundances of heavy ions (masses larger than He) in the solar wind provide information about physical processes occurring in the corona. Additionally, the charge state distributions of these heavy ions are sensitive to the temperature profiles of their respective source regions in the corona. Heavy ion dropouts are a relatively new class of solar wind events identified by both elemental and ionic charge state distributions. We have shown that their origins lie in large, closed coronal loops where processes such as gravitational settling dominate and can cause a mass-dependent fractionation pattern. In this study we consider and attempt to answer three fundamental questions concerning heavy ion dropouts: (1) 'where are the source loops located in the large-scale corona?'; (2) 'how does the interplay between coronal processes influence the end elemental abundances?'; and (3) 'what are the most probable release mechanisms'? We begin by analyzing the temporal and spatial variability of heavy ion dropouts and their correlation with heliospheric plasma and magnetic structures. Next we investigate the ordering of the elements inside dropouts with respect to mass, ionic charge state, and first ionization potential. Finally, we discuss these results in the context of the prevailing solar wind theories and the processes they posit that may be responsible for the release of coronal plasma into interplanetary space

  9. Survey of ionic charge states of solar energetic particle events during the first year of ACE

    International Nuclear Information System (INIS)

    Moebius, E.; Popecki, M.A.; Morris, D.; Galvin, A.B.; Heirtzler, D.; Kistler, L.M.; Siren, C.; Klecker, B.; Bogdanov, A.T.; Hovestadt, D.; Mason, G.M.; Dwyer, J.R.; Stone, E.C.

    2000-01-01

    The ionic charge state distributions of solar energetic particle events are determined with ACE SEPICA on an event by event basis, over the time period from launch through the end of 1998. Because of the large geometric factor of SEPICA the observations can be extended to events with very low fluxes. The study is confined to the most abundant species O, Ne, Mg, and Fe. Mean charge states for Fe are observed to vary between ≅11 for CME related events and ≅20 for small events that carry signatures of impulsive events. For these events all elements up to Mg, appear almost fully ionized. The charge states of all species follow the same trend as that of Fe in their variation from event to event. A comparison of observed mean charge states with a model assuming thermal equilibrium shows a general agreement with temperatures ranging from 1.2-10·10 6 K. However, noticeable deviations from charge states at a unique temperature for all species are seen for O at high and for Mg at both high and low charge states, which may suggest the presence of other processes. A distinct correlation is observed between the charge states and the overabundance of heavy ions in comparison with O. It remains puzzling that events with substantial deviations from coronal abundance accelerate almost fully stripped ions, which do not lend themselves easily to fractionation processes based on mass and charge

  10. Direct observations of the charge states of low energy solar particles

    Science.gov (United States)

    Gloeckler, G.; Fan, C. Y.; Hovestadt, D.

    1974-01-01

    The charge states of carbon and oxygen of solar origin have been measured directly in interplanetary space. At 100 keV per nucleon the C(+5)/C(+6) and O(+7)/O(+8) ratios are 1.8 and 1.6, respectively. Abundance ratios of low energy heavy nuclei to He are found which are significantly larger than the corresponding photospheric values. The enhancement of O/He is 35, and both Si/He and Fe/He are overabundant by a factor of 100. To explain these observations a mechanism is proposed which first preferentially accelerates heavy ions and is followed by either storage of these ions in the coronal regions or strong adiabatic deceleration.

  11. Low-charge-state linac

    Energy Technology Data Exchange (ETDEWEB)

    Shepard, K.W.; Kim, J.W.

    1995-08-01

    A design is being developed for a low-charge-state linac suitable for injecting ATLAS with a low-charge-state, radioactive beam. Initial work indicates that the existing ATLAS interdigital superconducting accelerating structures, together with the superconducting quadrupole transverse focussing element discussed above, provides a basis for a high-performance low-charge-state linac. The initial 2 or 3 MV of such a linac could be based on a normally-conducting, low-frequency RFQ, possibly combined with 24-MHz superconducting interdigital structures. Beam dynamics studies of the whole low-charge-state post-accelerator section were carried out in early FY 1995.

  12. Coronal Mass Ejections

    CERN Document Server

    Kunow, H; Linker, J. A; Schwenn, R; Steiger, R

    2006-01-01

    It is well known that the Sun gravitationally controls the orbits of planets and minor bodies. Much less known, however, is the domain of plasma fields and charged particles in which the Sun governs a heliosphere out to a distance of about 15 billion kilometers. What forces activates the Sun to maintain this power? Coronal Mass Ejections (CMEs) and their descendants are the troops serving the Sun during high solar activity periods. This volume offers a comprehensive and integrated overview of our present knowledge and understanding of Coronal Mass Ejections (CMEs) and their descendants, Interplanetary CMEs (ICMEs). It results from a series of workshops held between 2000 and 2004. An international team of about sixty experimenters involved e.g. in the SOHO, ULYSSES, VOYAGER, PIONEER, HELIOS, WIND, IMP, and ACE missions, ground observers, and theoreticians worked jointly on interpreting the observations and developing new models for CME initiations, development, and interplanetary propagation. The book provides...

  13. Charge states of ions, and mechanisms of charge ordering transitions

    Science.gov (United States)

    Pickett, Warren E.; Quan, Yundi; Pardo, Victor

    2014-07-01

    To gain insight into the mechanism of charge ordering transitions, which conventionally are pictured as a disproportionation of an ion M as 2Mn+→M(n+1)+ + M(n-1)+, we (1) review and reconsider the charge state (or oxidation number) picture itself, (2) introduce new results for the putative charge ordering compound AgNiO2 and the dual charge state insulator AgO, and (3) analyze the cationic occupations of the actual (not formal) charge, and work to reconcile the conundrums that arise. We establish that several of the clearest cases of charge ordering transitions involve no disproportion (no charge transfer between the cations, and hence no charge ordering), and that the experimental data used to support charge ordering can be accounted for within density functional-based calculations that contain no charge transfer between cations. We propose that the charge state picture retains meaning and importance, at least in many cases, if one focuses on Wannier functions rather than atomic orbitals. The challenge of modeling charge ordering transitions with model Hamiltonians isdiscussed.

  14. COMPOSITION OF CORONAL MASS EJECTIONS

    Energy Technology Data Exchange (ETDEWEB)

    Zurbuchen, T. H.; Weberg, M.; Lepri, S. T. [Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI (United States); Von Steiger, R. [International Space Science Institute, Bern (Switzerland); Mewaldt, R. A. [California Institute of Technology, Pasadena, CA (United States); Antiochos, S. K. [Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD (United States)

    2016-07-20

    We analyze the physical origin of plasmas that are ejected from the solar corona. To address this issue, we perform a comprehensive analysis of the elemental composition of interplanetary coronal mass ejections (ICMEs) using recently released elemental composition data for Fe, Mg, Si, S, C, N, Ne, and He as compared to O and H. We find that ICMEs exhibit a systematic abundance increase of elements with first ionization potential (FIP) < 10 eV, as well as a significant increase of Ne as compared to quasi-stationary solar wind. ICME plasmas have a stronger FIP effect than slow wind, which indicates either that an FIP process is active during the ICME ejection or that a different type of solar plasma is injected into ICMEs. The observed FIP fractionation is largest during times when the Fe ionic charge states are elevated above Q {sub Fe} > 12.0. For ICMEs with elevated charge states, the FIP effect is enhanced by 70% over that of the slow wind. We argue that the compositionally hot parts of ICMEs are active region loops that do not normally have access to the heliosphere through the processes that give rise to solar wind. We also discuss the implications of this result for solar energetic particles accelerated during solar eruptions and for the origin of the slow wind itself.

  15. The Medical Examiner/Coroner's Guide for Contaminated Deceased Body Management.

    Science.gov (United States)

    Hanzlick, Randy; Nolte, Kurt; deJong, Joyce

    2009-12-01

    In the past few years, a number of publications and other resources have appeared concerning the management of mass fatality incidents. Some are geared toward the general management of incidents while others cover more specific topics such as decontamination procedures. Still others cover selected agents, including chemical, biologic, or radiologic ones. Few publications have been written specifically for medical examiners and coroners. The Medical Examiner and Coroner's Guide for Contaminated Deceased Body Management is written specifically for the medical examiner or coroner who will be in charge of investigations of fatalities that result from terrorism or other events that result in contaminated remains. In some such cases, agents may be used that will require mitigation of environmental hazards and decontamination of human bodies. To that end, this Guide provides information and suggestions that may be useful in understanding the principles involved in decontamination procedures, recognizing that it may not be the medical examiner or coroner staff who actually conducts decontamination procedures. The suggestions in this guide may differ slightly from those in other publications. However, those who have contributed to this guide believe that the recommendations are practical, workable, have a scientific basis, and do not differ much in substance when compared with other relevant publications. The contents of this Guide may be reproduced for practical use but the Guide may not be sold and it may not be cited for advertisement purposes. Reference to specific commercial products is for informational purposes only and does not constitute endorsement of the product or company which produces the product. The recommendations contained in this Guide are not mandated nor are they required by federal, state, or local law. Rather, the recommendations are intended to assist medical examiners and coroners for the purposes of planning and providing a set of reasonable

  16. EVOLUTION OF THE RELATIONSHIPS BETWEEN HELIUM ABUNDANCE, MINOR ION CHARGE STATE, AND SOLAR WIND SPEED OVER THE SOLAR CYCLE

    International Nuclear Information System (INIS)

    Kasper, J. C.; Stevens, M. L.; Korreck, K. E.; Maruca, B. A.; Kiefer, K. K.; Schwadron, N. A.; Lepri, S. T.

    2012-01-01

    The changing relationships between solar wind speed, helium abundance, and minor ion charge state are examined over solar cycle 23. Observations of the abundance of helium relative to hydrogen (A He ≡ 100 × n He /n H ) by the Wind spacecraft are used to examine the dependence of A He on solar wind speed and solar activity between 1994 and 2010. This work updates an earlier study of A He from 1994 to 2004 to include the recent extreme solar minimum and broadly confirms our previous result that A He in slow wind is strongly correlated with sunspot number, reaching its lowest values in each solar minima. During the last minimum, as sunspot numbers reached their lowest levels in recent history, A He continued to decrease, falling to half the levels observed in slow wind during the previous minimum and, for the first time observed, decreasing even in the fastest solar wind. We have also extended our previous analysis by adding measurements of the mean carbon and oxygen charge states observed with the Advanced Composition Explorer spacecraft since 1998. We find that as solar activity decreased, the mean charge states of oxygen and carbon for solar wind of a given speed also fell, implying that the wind was formed in cooler regions in the corona during the recent solar minimum. The physical processes in the coronal responsible for establishing the mean charge state and speed of the solar wind have evolved with solar activity and time.

  17. ANATOMY OF DEPLETED INTERPLANETARY CORONAL MASS EJECTIONS

    Energy Technology Data Exchange (ETDEWEB)

    Kocher, M.; Lepri, S. T.; Landi, E.; Zhao, L.; Manchester, W. B. IV, E-mail: mkocher@umich.edu [Department of Climate and Space Sciences and Engineering, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109-2143 (United States)

    2017-01-10

    We report a subset of interplanetary coronal mass ejections (ICMEs) containing distinct periods of anomalous heavy-ion charge state composition and peculiar ion thermal properties measured by ACE /SWICS from 1998 to 2011. We label them “depleted ICMEs,” identified by the presence of intervals where C{sup 6+}/C{sup 5+} and O{sup 7+}/O{sup 6+} depart from the direct correlation expected after their freeze-in heights. These anomalous intervals within the depleted ICMEs are referred to as “Depletion Regions.” We find that a depleted ICME would be indistinguishable from all other ICMEs in the absence of the Depletion Region, which has the defining property of significantly low abundances of fully charged species of helium, carbon, oxygen, and nitrogen. Similar anomalies in the slow solar wind were discussed by Zhao et al. We explore two possibilities for the source of the Depletion Region associated with magnetic reconnection in the tail of a CME, using CME simulations of the evolution of two Earth-bound CMEs described by Manchester et al.

  18. The Solar Connection of Enhanced Heavy Ion Charge States in the Interplanetary Medium: Implications for the Flux-Rope Structure of CMEs

    Science.gov (United States)

    Gopalswamy, N.; Makela, P.; Akiyama, S.; Xie, H.; Yashiro, S.; Reinard, A. A.

    2013-01-01

    We investigated a set of 54 interplanetary coronal mass ejection (ICME) events whose solar sources are very close to the disk center (within +/- 15deg from the central meridian). The ICMEs consisted of 23 magnetic-cloud (MC) events and 31 non-MC events. Our analyses suggest that the MC and non-MC ICMEs have more or less the same eruption characteristics at the Sun in terms of soft X-ray flares and CMEs. Both types have significant enhancements in ion charge states, although the non-MC structures have slightly lower levels of enhancement. The overall duration of charge-state enhancement is also considerably smaller than that in MCs as derived from solar wind plasma and magnetic signatures. We find very good correlation between the Fe and O charge-state measurements and the flare properties such as soft X-ray flare intensity and flare temperature for both MCs and non-MCs. These observations suggest that both MC and non-MC ICMEs are likely to have a flux-rope structure and the unfavorable observational geometry may be responsible for the appearance of non-MC structures at 1 AU. We do not find any evidence for an active region expansion resulting in ICMEs lacking a flux-rope structure because the mechanism of producing high charge states and the flux-rope structure at the Sun is the same for MC and non-MC events.

  19. Nickel-hydrogen battery state of charge during low rate trickle charging

    Science.gov (United States)

    Lurie, C.; Foroozan, S.; Brewer, J.; Jackson, L.

    1996-01-01

    The NASA AXAF-I program requires high battery state of charge at launch. Traditional approaches to providing high state of charge, during prelaunch operations, require significant battery cooling. The use of active cooling, in the AXAF-I prelaunch environment, was considered and proved to be difficult to implement and very expensive. Accordingly alternate approaches were considered. An approach utilizing adiabatic charging and low rate trickle charge, was investigated and proved successful.

  20. Nickel-hydrogen battery state of charge during low rate trickle charging

    Energy Technology Data Exchange (ETDEWEB)

    Lurie, C.; Foroozan, S.; Brewer, J.; Jackson, L. [TRW Space and Electronics Group, Redondo Beach, CA (United States)

    1996-02-01

    The NASA AXAF-I program requires high battery state of charge at launch. Traditional approaches to providing high state of charge, during prelaunch operations, require significant battery cooling. The use of active cooling, in the AXAF-I prelaunch environment, was considered and proved to be difficult to implement and very expensive. Accordingly alternate approaches were considered. An approach utilizing adiabatic charging and low rate trickle charge, was investigated and proved successful.

  1. Solar wind heavy ions from energetic coronal events

    International Nuclear Information System (INIS)

    Bame, S.J.

    1978-01-01

    Ions heavier than those of He can be resolved in the solar wind with electrostatic E/q analyzers when the local thermal temperatures are low. Ordinarily this condition prevails in the low speed solar wind found between high speed streams, i.e. the interstream, IS, solar wind. Various ions of O, Si and Fe are resolved in IS heavy ion spectra. Relative ion peak intensities indicate that the O ionization state is established in the IS coronal source regions at approx. 2.1 x 10 6 K while the state of Fe is frozen in at approx. 1.5 x 10 6 K farther out. Occasionally, anomalous spectra are observed in which the usually third most prominent ion peak, O 8+ , is depressed as are the Fe peaks ranging from Fe 12+ to Fe 7+ . A prominent peak in the usual Si 8+ position of IS spectra is self-consistently shown to be Fe 16+ . These features demonstrate that the ionization states were frozen in at higher than usual coronal temperatures. The source regions of these hot heavy ion spectra are identified as energetic coronal events including flares and nonflare coronal mass ejections. 24 references

  2. Efficient charge generation by relaxed charge-transfer states at organic interfaces

    KAUST Repository

    Vandewal, Koen

    2013-11-17

    Interfaces between organic electron-donating (D) and electron-accepting (A) materials have the ability to generate charge carriers on illumination. Efficient organic solar cells require a high yield for this process, combined with a minimum of energy losses. Here, we investigate the role of the lowest energy emissive interfacial charge-transfer state (CT1) in the charge generation process. We measure the quantum yield and the electric field dependence of charge generation on excitation of the charge-transfer (CT) state manifold via weakly allowed, low-energy optical transitions. For a wide range of photovoltaic devices based on polymer:fullerene, small-molecule:C60 and polymer:polymer blends, our study reveals that the internal quantum efficiency (IQE) is essentially independent of whether or not D, A or CT states with an energy higher than that of CT1 are excited. The best materials systems show an IQE higher than 90% without the need for excess electronic or vibrational energy. © 2014 Macmillan Publishers Limited.

  3. Efficient charge generation by relaxed charge-transfer states at organic interfaces

    KAUST Repository

    Vandewal, Koen; Albrecht, Steve N.; Hoke, Eric T.; Graham, Kenneth; Widmer, Johannes; Douglas, Jessica D.; Schubert, Marcel; Mateker, William R.; Bloking, Jason T.; Burkhard, George F.; Sellinger, Alan; Frechet, Jean; Amassian, Aram; Riede, Moritz Kilian; McGehee, Michael D.; Neher, Dieter; Salleo, Alberto

    2013-01-01

    Interfaces between organic electron-donating (D) and electron-accepting (A) materials have the ability to generate charge carriers on illumination. Efficient organic solar cells require a high yield for this process, combined with a minimum of energy losses. Here, we investigate the role of the lowest energy emissive interfacial charge-transfer state (CT1) in the charge generation process. We measure the quantum yield and the electric field dependence of charge generation on excitation of the charge-transfer (CT) state manifold via weakly allowed, low-energy optical transitions. For a wide range of photovoltaic devices based on polymer:fullerene, small-molecule:C60 and polymer:polymer blends, our study reveals that the internal quantum efficiency (IQE) is essentially independent of whether or not D, A or CT states with an energy higher than that of CT1 are excited. The best materials systems show an IQE higher than 90% without the need for excess electronic or vibrational energy. © 2014 Macmillan Publishers Limited.

  4. Determination of Fe charge-state distributions in PLT by Bragg crystal x-ray spectroscopy

    International Nuclear Information System (INIS)

    Hill, K.W.; von Goeler, S.; Bitter, M.

    1978-08-01

    A curved-crystal Bragg x-ray spectrometer has been used to measure Kα or 1s-2p radiation from highly stripped Fe XVIII to Fe XXV impurity ions in the PLT tokamak. The spectrometer has sufficient energy resolution (approximately < 4 eV at 6400 eV) to distinguish between the different ionization states of iron by measuring the energy shift of the Kα x rays. The measured wavelengths agree well with theory and with spectra from solar flares and from laser-produced plasmas. The distribution of Fe charge states in the center of the discharge has been inferred from a comparison of the measured x-ray spectrum with theory. The shape of the spectrum depends strongly on electron temperature (T/sub e/) in the range T/sub e/ = 800 to 1500 eV. Within the factor of two uncertainty in L-shell ionization cross sections, measured intensities agree with theory, which is based on coronal equilibrium, indicating that the ion life-time in the center of the plasma is approximately equal to or greater than the equilibration time

  5. The first coronation churches of medieval Serbia

    Directory of Open Access Journals (Sweden)

    Kalić Jovanka

    2017-01-01

    Full Text Available The medieval ceremony of coronation as a rule took place in the most important church of a realm. The sites of the coronation of Serbian rulers before the establishment of the Žiča monastery church as the coronation church of Serbian kings in the first half of the thirteenth century have not been reliably identified so far. Based on the surviving medieval sources and the archaeological record, this paper provides background information about the titles of Serbian rulers prior to the creation of the Nemanjić state, and proposes that Stefan, son of the founder of the Nemanjić dynasty, was crowned king (1217 in the church of St Peter in Ras.

  6. Coronal Seismology: The Search for Propagating Waves in Coronal Loops

    Science.gov (United States)

    Schad, Thomas A.; Seeley, D.; Keil, S. L.; Tomczyk, S.

    2007-05-01

    We report on Doppler observations of the solar corona obtained in the Fe XeXIII 1074.7nm coronal emission line with the HAO Coronal Multi-Channel Polarimeter (CoMP) mounted on the NSO Coronal One Shot coronagraph located in the Hilltop Facility of NSO/Sacramento Peak. The COMP is a tunable filtergraph instrument that records the entire corona from the edge of the occulting disk at approximately 1.03 Rsun out to 1.4 Rsun with a spatial resolution of about 4” x 4”. COMP can be rapidly scanned through the spectral line while recording orthogonal states of linear and circular polarization. The two dimensional spatial resolution allows us to correlate temporal fluctuations observed in one part of the corona with those seen at other locations, in particular along coronal loops. Using cross spectral analysis we find that the observations reveal upward propagating waves that are characterized by Doppler shifts with rms velocities of 0.3 km/s, peak wave power in the 3-5 mHz frequency range, and phase speeds 1-3 Mm/s. The wave trajectories are consistent with the direction of the magnetic field inferred from the linear polarization measurements. We discuss the phase and coherence of these waves as a function of height in the corona and relate our findings to previous observations. The observed waves appear to be Alfvenic in character. "Thomas Schad was supported through the National Solar Observatory Research Experiences for Undergraduate (REU) site program, which is co-funded by the Department of Defense in partnership with the National Science Foundation REU Program." Daniel Seeley was supported through the National Solar Observatory Research Experience for Teachers (RET) site program, which is funded by the National Science Foundation RET program.

  7. A DATA-DRIVEN ANALYTIC MODEL FOR PROTON ACCELERATION BY LARGE-SCALE SOLAR CORONAL SHOCKS

    Energy Technology Data Exchange (ETDEWEB)

    Kozarev, Kamen A. [Smithsonian Astrophysical Observatory (United States); Schwadron, Nathan A. [Institute for the Study of Earth, Oceans, and Space, University of New Hampshire (United States)

    2016-11-10

    We have recently studied the development of an eruptive filament-driven, large-scale off-limb coronal bright front (OCBF) in the low solar corona, using remote observations from the Solar Dynamics Observatory ’s Advanced Imaging Assembly EUV telescopes. In that study, we obtained high-temporal resolution estimates of the OCBF parameters regulating the efficiency of charged particle acceleration within the theoretical framework of diffusive shock acceleration (DSA). These parameters include the time-dependent front size, speed, and strength, as well as the upstream coronal magnetic field orientations with respect to the front’s surface normal direction. Here we present an analytical particle acceleration model, specifically developed to incorporate the coronal shock/compressive front properties described above, derived from remote observations. We verify the model’s performance through a grid of idealized case runs using input parameters typical for large-scale coronal shocks, and demonstrate that the results approach the expected DSA steady-state behavior. We then apply the model to the event of 2011 May 11 using the OCBF time-dependent parameters derived by Kozarev et al. We find that the compressive front likely produced energetic particles as low as 1.3 solar radii in the corona. Comparing the modeled and observed fluences near Earth, we also find that the bulk of the acceleration during this event must have occurred above 1.5 solar radii. With this study we have taken a first step in using direct observations of shocks and compressions in the innermost corona to predict the onsets and intensities of solar energetic particle events.

  8. Charge state distributions from highly charged ions channeled at a metal surface

    International Nuclear Information System (INIS)

    Folkerts, L.; Meyer, F.W.; Schippers, S.

    1994-01-01

    The vast majority of the experimental work in the field of multicharged ion-surface interactions, to date, has focused on x-ray and particularly on electron emission. These experiments include measurements of the total electron yield, the emission statistics of the electrons, and, most of all, the electron energy distributions. So far, little attention has been paid to the fate of the multicharged projectile ions after the scattering. To our knowledge, the only measurement of the charge state distribution of the scattered ions is the pioneering experiment of de Zwart et al., who measured the total yield of scattered 1+, 2+, and 3+ ions as a function of the primary charge state q (q = 1--11) for 20 key Ne, Ar, and Kr ions after reflection from a polycrystalline tungsten target. Their main finding is the sudden onset of scattered 3+ ions when inner-shell vacancies are present in the primary particles. This suggests that a certain fraction of the inner-shell vacancies survives the entire collision event, and decays via autoionization on the outgoing path. Since the projectiles scattered in the neutral charge state could not be detected in the experiment of de Zwart et al., they were not able to provide absolute charge state fractions. In our present experiment, we focus on the scattered projectiles, measuring both the final charge state and the total scattering angle with a single 2D position sensitive detector (PSD). This method gives us the number of positive, as well as neutral and negative, scattered ions, thus allowing us to extract absolute charge state fractions. Using a well-prepared single Au(110) crystal and a grazing incidence geometry, we were able to observe surface channeling along the [001] channels

  9. Evaluation of several state-of-charge algorithms

    Science.gov (United States)

    Espinosa, J. M.; Martin, M. E.; Burke, A. F.

    1988-09-01

    One of the important needs in marketing an electric vehicle is a device which reliably indicates battery state-of-charge for all types of driving. The purpose of the state-of-charge indicator is analogous to a gas gauge in an internal combustion engine powered vehicle. Many different approaches have been tried to accurately predict battery state-of-charge. This report evaluates several of these approaches. Four different algorithms were implemented into software on an IBM PC and tested using a battery test database for ALCO 2200 lead-acid batteries generated at the INEL. The database was obtained under controlled conditions which compare with the battery response in real EV use. Each algorithm is described in detail as to theory and operational functionality. Also discussed is the hardware and data requirements particular to implementing the individual algorithms. The algorithms were evaluated for accuracy using constant power, stepped power, and simulated vehicle (SFUDS79) discharge profiles. Attempts were made to explain the cause of differences between the predicted and actual state-of-charge and to provide possible remedies to correct them. Recommendations for future work on battery state-of-charge indicators are presented that utilize the hardware and software now in place in the INEL Battery Laboratory.

  10. Low-charge-state RFQ injector

    Energy Technology Data Exchange (ETDEWEB)

    Shepard, K.W.; Kim, J.W.

    1995-08-01

    Preliminary design work was done for a short, normally-conducting RFQ entrance section for a low-charge-state linac. Early results indicate that a low- frequency (12 MHz) RFQ, operated on a high-voltage platform, and injected with a pre-bunched beam, can provide ATLAS quality beams of ions of charge-to-mass ratio less than 1/132.

  11. Can coronal hole spicules reach coronal temperatures?

    Science.gov (United States)

    Madjarska, M. S.; Vanninathan, K.; Doyle, J. G.

    2011-08-01

    Aims: The present study aims to provide observational evidence of whether coronal hole spicules reach coronal temperatures. Methods: We combine multi-instrument co-observations obtained with the SUMER/SoHO and with the EIS/SOT/XRT/Hinode. Results: The analysed three large spicules were found to be comprised of numerous thin spicules that rise, rotate, and descend simultaneously forming a bush-like feature. Their rotation resembles the untwisting of a large flux rope. They show velocities ranging from 50 to 250 kms-1. We clearly associated the red- and blue-shifted emissions in transition region lines not only with rotating but also with rising and descending plasmas. Our main result is that these spicules although very large and dynamic, are not present in the spectral lines formed at temperatures above 300 000 K. Conclusions: In this paper we present the analysis of three Ca ii H large spicules that are composed of numerous dynamic thin spicules but appear as macrospicules in lower resolution EUV images. We found no coronal counterpart of these and smaller spicules. We believe that the identification of phenomena that have very different origins as macrospicules is due to the interpretation of the transition region emission, and especially the He ii emission, wherein both chromospheric large spicules and coronal X-ray jets are present. We suggest that the recent observation of spicules in the coronal AIA/SDO 171 Å and 211 Å channels probably comes from the existence of transition region emission there. Movie is available in electronic form at http://www.aanda.org

  12. Charge state of ions scattered by metal surface

    International Nuclear Information System (INIS)

    Kishinevsky, L.M.; Parilis, E.S.; Verleger, V.K.

    1976-01-01

    A model for description of charge distributions for scattering of heavy ions in the keV region, on metal surfaces developing and improving the method of Van der Weg and Bierman, and taking into account the connection between the ion charge state and scattering kinematics, is proposed. It is shown that multiple charged particles come from ions with a vacancy in the inner shell while the outer shell vacancies give only single charged ions and neutrals. The approximately linear increase of degree of ionization with normal velocity, and the non-monotonic charge dependence of the energy spectrum established by Chicherov and Buck et al is explained by considering irreversible neutralization in the depth of the metal, taking into account the connection of the charge state with the shape of trajectory and its location relative to the metal surface. The dependence of charge state on surface structure is discussed. Some new experiments are proposed. (author)

  13. [Probabilistic calculations of biomolecule charge states that generate mass spectra of multiply charged ions].

    Science.gov (United States)

    Raznikova, M O; Raznikov, V V

    2015-01-01

    In this work, information relating to charge states of biomolecule ions in solution obtained using the electrospray ionization mass spectrometry of different biopolymers is analyzed. The data analyses have mainly been carried out by solving an inverse problem of calculating the probabilities of retention of protons and other charge carriers by ionogenic groups of biomolecules with known primary structures. The approach is a new one and has no known to us analogues. A program titled "Decomposition" was developed and used to analyze the charge distribution of ions of native and denatured cytochrome c mass spectra. The possibility of splitting of the charge-state distribution of albumin into normal components, which likely corresponds to various conformational states of the biomolecule, has been demonstrated. The applicability criterion for using previously described method of decomposition of multidimensional charge-state distributions with two charge carriers, e.g., a proton and a sodium ion, to characterize the spatial structure of biopolymers in solution has been formulated. In contrast to known mass-spectrometric approaches, this method does not require the use of enzymatic hydrolysis or collision-induced dissociation of the biopolymers.

  14. Coronal ``Wave'': Magnetic Footprint of a Coronal Mass Ejection?

    Science.gov (United States)

    Attrill, Gemma D. R.; Harra, Louise K.; van Driel-Gesztelyi, Lidia; Démoulin, Pascal

    2007-02-01

    We investigate the properties of two ``classical'' EUV Imaging Telescope (EIT) coronal waves. The two source regions of the associated coronal mass ejections (CMEs) possess opposite helicities, and the coronal waves display rotations in opposite senses. We observe deep core dimmings near the flare site and also widespread diffuse dimming, accompanying the expansion of the EIT wave. We also report a new property of these EIT waves, namely, that they display dual brightenings: persistent ones at the outermost edge of the core dimming regions and simultaneously diffuse brightenings constituting the leading edge of the coronal wave, surrounding the expanding diffuse dimmings. We show that such behavior is consistent with a diffuse EIT wave being the magnetic footprint of a CME. We propose a new mechanism where driven magnetic reconnections between the skirt of the expanding CME magnetic field and quiet-Sun magnetic loops generate the observed bright diffuse front. The dual brightenings and the widespread diffuse dimming are identified as innate characteristics of this process.

  15. Formation of coronal cavities

    International Nuclear Information System (INIS)

    An, C.H.; Suess, S.T.; Tandberg-Hanssen, E.; Steinolfson, R.S.

    1986-01-01

    A theoretical study of the formation of a coronal cavity and its relation to a quiescent prominence is presented. It is argued that the formation of a cavity is initiated by the condensation of plasma which is trapped by the coronal magnetic field in a closed streamer and which then flows down to the chromosphere along the field lines due to lack of stable magnetic support against gravity. The existence of a coronal cavity depends on the coronal magnetic field strength; with low strength, the plasma density is not high enough for condensation to occur. Furthermore, we suggest that prominence and cavity material is supplied from the chromospheric level. Whether a coronal cavity and a prominence coexist depends on the magnetic field configuration; a prominence requires stable magnetic support

  16. Charge-state correlated cross sections for the production of low-velocity highly charged Ne ions by heavy-ion bombardment

    International Nuclear Information System (INIS)

    Gray, T.J.; Cocke, C.L.; Justiniano, E.

    1980-01-01

    We report measured cross sections for the collisional production of highly charged low-velocity Ne recoil ions resulting from the bombardment of a thin Ne gas target by highly charged 1-MeV/amu C, N, O, and F projectiles. The measurements were made using time-of-flight techniques which allowed the simultaneous identification of the final charge state of both the low-velocity recoil ion and the high-velocity projectile for each collision event. For a given incident-projectile charge state, the recoil charge-state distribution is very dependent upon the final charge state of the projectile. Single- and double-electron capture events by incident bare nuclei and projectile K-shell ionization during the collision cause large shifts in the recoil charge-state distributions toward higher charge states. A previously proposed energy-deposition model is modified to include the effects of projectile charge-changing collisions during the collision for bare and hydrogenlike projectiles and is used to discuss the present experimental results

  17. Interfacial Charge Transfer States in Condensed Phase Systems

    Science.gov (United States)

    Vandewal, Koen

    2016-05-01

    Intermolecular charge transfer (CT) states at the interface between electron-donating (D) and electron-accepting (A) materials in organic thin films are characterized by absorption and emission bands within the optical gap of the interfacing materials. CT states efficiently generate charge carriers for some D-A combinations, and others show high fluorescence quantum efficiencies. These properties are exploited in organic solar cells, photodetectors, and light-emitting diodes. This review summarizes experimental and theoretical work on the electronic structure and interfacial energy landscape at condensed matter D-A interfaces. Recent findings on photogeneration and recombination of free charge carriers via CT states are discussed, and relations between CT state properties and optoelectronic device parameters are clarified.

  18. The use of iron charge state changes as a tracer for solar wind entry and energization within the magnetosphere

    Directory of Open Access Journals (Sweden)

    T. A. Fritz

    Full Text Available The variation of the charge state of iron [Fe] ions is used to trace volume elements of plasma in the solar wind into the magnetosphere and to determine the time scales associated with the entry into and the action of the magnetospheric energization process working on these plasmas. On 2–3 May 1998 the Advanced Composition Explorer (ACE spacecraft located at the L1 libration point observed a series of changes to the average charge state of the element Fe in the solar wind plasma reflecting variation in the coronal temperature of their original source. Over the period of these two days the average Fe charge state was observed to vary from + 15 to + 6 both at the Polar satellite in the high latitude dayside magnetosphere and at ACE. During a period of southward IMF the observations at Polar inside the magnetosphere of the same Fe charge state were simultaneous with those at ACE delayed by the measured convection speed of the solar wind to the subsolar magnetopause. Comparing the phase space density as a function of energy at both ACE and Polar has indicated that significant energization of the plasma occurred on very rapid time scales. Energization at constant phase space density by a factor of 5 to 10 was observed over a range of energy from a few keV to about 1 MeV. For a detector with a fixed energy threshold in the range from 10 keV to a few hundred keV this observed energization will appear as a factor of ~103 increase in its counting rate. Polar observations of very energetic O+ ions at the same time indicate that this energization process must be occurring in the high latitude cusp region inside the magnetosphere and that it is capable of energizing ionospheric ions at the same time.

    Key words. Magnetospheric physics (magnetopause, cusp, and boundary layers; magnetospheric configuration and dynamics; solar wind-magnetosphere interactions

  19. Low charge state heavy ion production with sub-nanosecond laser.

    Science.gov (United States)

    Kanesue, T; Kumaki, M; Ikeda, S; Okamura, M

    2016-02-01

    We have investigated laser ablation plasma of various species using nanosecond and sub-nanosecond lasers for both high and low charge state ion productions. We found that with sub-nanosecond laser, the generated plasma has a long tail which has low charge state ions determined by an electrostatic ion analyzer even under the laser irradiation condition for highly charged ion production. This can be caused by insufficient laser absorption in plasma plume. This property might be suitable for low charge state ion production. We used a nanosecond laser and a sub-nanosecond laser for low charge state ion production to investigate the difference of generated plasma using the Zirconium target.

  20. Low charge state heavy ion production with sub-nanosecond laser

    Energy Technology Data Exchange (ETDEWEB)

    Kanesue, T., E-mail: tkanesue@bnl.gov; Okamura, M. [Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973 (United States); Kumaki, M. [Research Institute for Science and Engineering, Waseda University, Tokyo 169-8555 (Japan); Nishina Center for Accelerator-Based Science, RIKEN, Saitama 351-0198 (Japan); Ikeda, S. [Nishina Center for Accelerator-Based Science, RIKEN, Saitama 351-0198 (Japan); Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Kanagawa 226-8503 (Japan)

    2016-02-15

    We have investigated laser ablation plasma of various species using nanosecond and sub-nanosecond lasers for both high and low charge state ion productions. We found that with sub-nanosecond laser, the generated plasma has a long tail which has low charge state ions determined by an electrostatic ion analyzer even under the laser irradiation condition for highly charged ion production. This can be caused by insufficient laser absorption in plasma plume. This property might be suitable for low charge state ion production. We used a nanosecond laser and a sub-nanosecond laser for low charge state ion production to investigate the difference of generated plasma using the Zirconium target.

  1. Concept for high-charge-state ion induction accelerators

    International Nuclear Information System (INIS)

    Logan, B.G.; Perry, M.D.; Caporaso, G.J.

    1996-01-01

    This work describes a particular concept for ion induction linac accelerators using high-charge-state ions produced by an intense, short pulse laser, and compares the costs of a modular driver system producing 6.5 MJ for a variety of ion masses and charge states using a simple but consistent cost model

  2. Simulating coronal condensation dynamics in 3D

    Science.gov (United States)

    Moschou, S. P.; Keppens, R.; Xia, C.; Fang, X.

    2015-12-01

    We present numerical simulations in 3D settings where coronal rain phenomena take place in a magnetic configuration of a quadrupolar arcade system. Our simulation is a magnetohydrodynamic simulation including anisotropic thermal conduction, optically thin radiative losses, and parametrised heating as main thermodynamical features to construct a realistic arcade configuration from chromospheric to coronal heights. The plasma evaporation from chromospheric and transition region heights eventually causes localised runaway condensation events and we witness the formation of plasma blobs due to thermal instability, that evolve dynamically in the heated arcade part and move gradually downwards due to interchange type dynamics. Unlike earlier 2.5D simulations, in this case there is no large scale prominence formation observed, but a continuous coronal rain develops which shows clear indications of Rayleigh-Taylor or interchange instability, that causes the denser plasma located above the transition region to fall down, as the system moves towards a more stable state. Linear stability analysis is used in the non-linear regime for gaining insight and giving a prediction of the system's evolution. After the plasma blobs descend through interchange, they follow the magnetic field topology more closely in the lower coronal regions, where they are guided by the magnetic dips.

  3. Charge state of oxide layer of SIMOX-structures

    CERN Document Server

    Askinazi, A Y; Dmitriev, V A; Miloglyadova, L V

    2001-01-01

    The charge state of the oxide layer of the SIMOX-structures, obtained in the course of forming the oxide layers, bricked up in the silicon volume, through the oxygen ions implantation into the Si, is studied. The charge state of the given structures is studied through the method of the layer-by-layer profiling, which makes it possible to obtain the dependence of the plane zones potential on the oxide layer thickness. It is established, that during the process of the SIMOX-structures formation in the oxide layer near the boundary with the Si there appear defects, responsible for the charge. The radiation from the near-the-ultraviolet (NUV) area without the applied electric field neutralizes the given charge. The simultaneous impact of the NUV-radiation and electric field leads to the formation of significantly positive charge

  4. Ground state of charged Base and Fermi fluids in strong coupling

    International Nuclear Information System (INIS)

    Mazighi, R.

    1982-03-01

    The ground state and excited states of the charged Bose gas were studied (wave function, equation of state, thermodynamics, application of Feynman theory). The ground state of the charged Fermi gas was also investigated together with the miscibility of charged Bose and Fermi gases at 0 deg K (bosons-bosons, fermions-bosons and fermions-fermions) [fr

  5. MHD Simulations of the Eruption of Coronal Flux Ropes under Coronal Streamers

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Yuhong, E-mail: yfan@ucar.edu [High Altitude Observatory, National Center for Atmospheric Research, 3080 Center Green Drive, Boulder, CO 80301 (United States)

    2017-07-20

    Using three-dimensional magnetohydrodynamic (MHD) simulations, we investigate the eruption of coronal flux ropes underlying coronal streamers and the development of a prominence eruption. We initialize a quasi-steady solution of a coronal helmet streamer, into which we impose at the lower boundary the slow emergence of a part of a twisted magnetic torus. As a result, a quasi-equilibrium flux rope is built up under the streamer. With varying streamer sizes and different lengths and total twists of the flux rope that emerges, we found different scenarios for the evolution from quasi-equilibrium to eruption. In the cases with a broad streamer, the flux rope remains well confined until there is sufficient twist such that it first develops the kink instability and evolves through a sequence of kinked, confined states with increasing height until it eventually develops a “hernia-like” ejective eruption. For significantly twisted flux ropes, prominence condensations form in the dips of the twisted field lines due to runaway radiative cooling. Once formed, the prominence-carrying field becomes significantly non-force-free due to the weight of the prominence, despite having low plasma β . As the flux rope erupts, the prominence erupts, showing substantial draining along the legs of the erupting flux rope. The prominence may not show a kinked morphology even though the flux rope becomes kinked. On the other hand, in the case with a narrow streamer, the flux rope with less than one wind of twist can erupt via the onset of the torus instability.

  6. Electron beam charge state amplifier (EBQA)--a conceptual evaluation

    International Nuclear Information System (INIS)

    Dooling, J. C.

    1998-01-01

    A concept is presented for stripping low-energy, radioactive ions from 1+ to higher charge states. Referred to as an Electron Beam Charge State Amplifier (EBQA), this device accepts a continuous beam of singly-charged, radioactive ions and passes them through a high-density electron beam confined by a solenoidal magnetic field. Singly-charged ions may be extracted from standard Isotope-Separator-Online (ISOL) sources. An EBQA is potentially useful for increasing the charge state of ions prior to injection into post-acceleration stages at ISOL radioactive beam facilities. The stripping efficiency from q=1+ to 2+ (η 12 ) is evaluated as a function of electron beam radius at constant current with solenoid field, injected ion energy, and ion beam emittance used as parameters. Assuming a 5 keV, 1 A electron beam, η 12 = 0.38 for 0.1 keV, 132 Xe ions passing through an 8 Tesla solenoid, 1 m in length. Multi-pass configurations to achieve 3+ or 4+ charge states are also conceivable. The calculated efficiencies depend inversely on the initial ion beam emittances. The use of a helium-buffer-gas, ion-guide stage to improve the brightness of the 1+ beams [1] may enhance the performance of an EBQA

  7. Steady three-fluid coronal expansion for nonspherical geometries

    International Nuclear Information System (INIS)

    Joselyn, J.; Holzer, T.E.

    1978-01-01

    A steady three-fluid model of the solar coronal expansionk in which 4 He ++ ions (alphas) are treated as a nonminor species, is developed for nonspherically symmetric flow geometries of the general sort thought to be characteristic of coronal holes. It is found that the very high mass fluxes in the low corona, which are associated with rapidly diverging flow geometries, lead to a locally enhanced frictional coupling between protons and alphas and consequently to a significant reduction of the He/H abundance ratio in the lower corona from that normally predicted by multifluid models. In the models considered, the frictional drag on the protons by the alphas (a process neglected in most studies) is found to play an important role near the sun. Heavy ions, other than alphas, are treated as minor species and are seen to exhibit varying responses to the rapidly diverging flow geometries, depending on the ion mass and charge. As for the protons, the frictional effect of the alphas on the heavier ions is found to be significant in the models considered

  8. Increasing Protein Charge State When Using Laser Electrospray Mass Spectrometry

    Science.gov (United States)

    Karki, Santosh; Flanigan, Paul M.; Perez, Johnny J.; Archer, Jieutonne J.; Levis, Robert J.

    2015-05-01

    Femtosecond (fs) laser vaporization is used to transfer cytochrome c, myoglobin, lysozyme, and ubiquitin from the condensed phase into an electrospray (ES) plume consisting of a mixture of a supercharging reagent, m-nitrobenzyl alcohol ( m-NBA), and trifluoroacetic acid (TFA), acetic acid (AA), or formic acid (FA). Interaction of acid-sensitive proteins like cytochrome c and myoglobin with the highly charged ES droplets resulted in a shift to higher charge states in comparison with acid-stable proteins like lysozyme and ubiquitin. Laser electrospray mass spectrometry (LEMS) measurements showed an increase in both the average charge states (Zavg) and the charge state with maximum intensity (Zmode) for acid-sensitive proteins compared with conventional electrospray ionization mass spectrometry (ESI-MS) under equivalent solvent conditions. A marked increase in ion abundance of higher charge states was observed for LEMS in comparison with conventional electrospray for cytochrome c (ranging from 19+ to 21+ versus 13+ to 16+) and myoglobin (ranging from 19+ to 26+ versus 18+ to 21+) using an ES solution containing m-NBA and TFA. LEMS measurements as a function of electrospray flow rate yielded increasing charge states with decreasing flow rates for cytochrome c and myoglobin.

  9. Coronal Waves and Oscillations

    Directory of Open Access Journals (Sweden)

    Nakariakov Valery M.

    2005-07-01

    Full Text Available Wave and oscillatory activity of the solar corona is confidently observed with modern imaging and spectral instruments in the visible light, EUV, X-ray and radio bands, and interpreted in terms of magnetohydrodynamic (MHD wave theory. The review reflects the current trends in the observational study of coronal waves and oscillations (standing kink, sausage and longitudinal modes, propagating slow waves and fast wave trains, the search for torsional waves, theoretical modelling of interaction of MHD waves with plasma structures, and implementation of the theoretical results for the mode identification. Also the use of MHD waves for remote diagnostics of coronal plasma - MHD coronal seismology - is discussed and the applicability of this method for the estimation of coronal magnetic field, transport coefficients, fine structuring and heating function is demonstrated.

  10. Effects of non-Maxwellian electron velocity distribution functions and nonspherical geometry on minor ions in the solar wind

    Science.gov (United States)

    Burgi, A.

    1987-01-01

    A previous model has shown that in order to account for the charge state distribution in the low-speed solar wind, a high coronal temperature is necessary and that this temperature peak goes together with a peak of nx/np in the corona. In the present paper, one of the assumptions made previously, i.e., that coronal electrons are Maxwellian, is relaxed, and a much cooler model is presented, which could account for the same oxygen charge states in the solar wind due to the inclusion of non-Maxwellian electrons. Also, due to a different choice of the coronal magnetic field geometry, this model would show no enhancement of the coronal nx/np. Results of the two models are then compared, and observational tests to distinguish between the two scenarios are proposed: comparison of directly measured coronal Te to charge state measurements in the solar wind, determination of the coronal nx/np measurement of ion speeds in the acceleration region of the solar wind, and measurement of the frozen-in silicon charge state distribution.

  11. Protecting a Diamond Quantum Memory by Charge State Control.

    Science.gov (United States)

    Pfender, Matthias; Aslam, Nabeel; Simon, Patrick; Antonov, Denis; Thiering, Gergő; Burk, Sina; Fávaro de Oliveira, Felipe; Denisenko, Andrej; Fedder, Helmut; Meijer, Jan; Garrido, Jose A; Gali, Adam; Teraji, Tokuyuki; Isoya, Junichi; Doherty, Marcus William; Alkauskas, Audrius; Gallo, Alejandro; Grüneis, Andreas; Neumann, Philipp; Wrachtrup, Jörg

    2017-10-11

    In recent years, solid-state spin systems have emerged as promising candidates for quantum information processing. Prominent examples are the nitrogen-vacancy (NV) center in diamond, phosphorus dopants in silicon (Si:P), rare-earth ions in solids, and V Si -centers in silicon-carbide. The Si:P system has demonstrated that its nuclear spins can yield exceedingly long spin coherence times by eliminating the electron spin of the dopant. For NV centers, however, a proper charge state for storage of nuclear spin qubit coherence has not been identified yet. Here, we identify and characterize the positively charged NV center as an electron-spin-less and optically inactive state by utilizing the nuclear spin qubit as a probe. We control the electronic charge and spin utilizing nanometer scale gate electrodes. We achieve a lengthening of the nuclear spin coherence times by a factor of 4. Surprisingly, the new charge state allows switching of the optical response of single nodes facilitating full individual addressability.

  12. Coroner Autopsy Findings Among Children and Adolescents of ...

    African Journals Online (AJOL)

    year retrospective study of coroner autopsies carried out on children I adolescents aged between 0-19 years, evaluated the pattern, causes and demographic features of childhood deaths in Rivers state, Nigeria. Methods A retrospective remew of ...

  13. Metastable states of plasma particles close to a charged surface

    Energy Technology Data Exchange (ETDEWEB)

    Shavlov, A. V., E-mail: shavlov@ikz.ru [The Institute of the Earth Cryosphere, RAS Siberian branch, 625000, P.O. 1230, Tyumen (Russian Federation); Tyumen State Oil and Gas University, 38, Volodarskogo St., 625000, Tyumen (Russian Federation); Dzhumandzhi, V. A. [The Institute of the Earth Cryosphere, RAS Siberian branch, 625000, P.O. 1230, Tyumen (Russian Federation)

    2015-09-15

    The free energy of the plasma particles and the charged surface that form an electroneutral system is calculated on the basis of the Poisson-Boltzmann equation. It is shown that, owing to correlation of light plasma particles near the charged surface and close to heavy particles of high charge, there can be metastable states in plasma. The corresponding phase charts of metastable states of the separate components of plasma, and plasma as a whole, are constructed. These charts depend on temperature, the charge magnitude, the size of the particles, and the share of the charge of the light carriers out of the total charge of the plasma particles.

  14. Recoil ion charge state distributions in low energy Arq+ - Ar collisions

    International Nuclear Information System (INIS)

    Vancura, J.; Marchetti, V.; Kostroun, V.O.

    1992-01-01

    We have measured the recoil ion charge state distributions in Ar q+ -- Ar (8≤q≤16) collisions at 2.3 qkeV and 0.18qkeV by time of flight (TOF) spectroscopy. For Ar 8-16+ , recoil ion charge states up to 6+ are clearly present, indicating that the 3p subshell in the target atom is being depleted, while for Ar 10-16+ , there is evidence that target 3s electrons are also being removed. Comparison of the recoil ion charge state spectra at 2.3 and 0.18 qkeV shows that for a given projectile charge, there is very little dependence of the observed recoil target charge state distribution on projectile energy

  15. An EBIS for charge state breeding in the SPES project

    Indian Academy of Sciences (India)

    The 'charge state breeder', BRIC (breeding ion charge) is in construction at the INFN section of Bari (Italy). It is based on EBIS scheme and it is designed to accept radioactive ion beam (RIB) with charge state +1 in a slow injection mode. This experiment can be considered as a first step towards the design and construction ...

  16. High charge state heavy ion production from a PIG source

    International Nuclear Information System (INIS)

    Bex, L.; Clark, D.J.; Ellsworth, C.E.; Flood, W.S.; Gough, R.A.; Holley, W.R.; Meriwether, J.R.; Morris, D.

    1975-03-01

    The comparison of pulsed vs. dc arc operation for nitrogen and argon shows a shift in charge distribution toward the higher charge states for the pulsed case. Tests with various magnetic field shapes along the arc column show a significant increase in high charge state output for a uniform field compared to the case with a field low at the cathodes. (U.S.)

  17. A high charge state heavy ion beam source for HIF

    International Nuclear Information System (INIS)

    Eylon, S.; Henestroza, E.

    1995-04-01

    A high current low emittance high charge state heavy ion beam source is being developed. This is designed to deliver HIF (heavy ion fusion) driver accelerator scale beam. Using high-charge-state beam in a driver accelerator for HIF may increase the acceleration efficiency, leading to a reduction in the driver accelerator size and cost. The proposed source system which consists of the gas beam electron stripper followed by a high charge state beam separator, can be added to existing single charge state, low emittance, high brightness ion sources and injectors. We shall report on the source physics design using 2D beam envelope simulations and experimental feasibility studies' results using a neutral gas stripper and a beam separator at the exit of the LBL 2 MV injector

  18. Deterministic Electrical Charge-State Initialization of Single Nitrogen-Vacancy Center in Diamond

    Directory of Open Access Journals (Sweden)

    Y. Doi

    2014-03-01

    Full Text Available Apart from applications in classical information-processing devices, the electrical control of atomic defects in solids at room temperature will have a tremendous impact on quantum devices that are based on such defects. In this study, we demonstrate the electrical manipulation of individual prominent representatives of such atomic solid-state defects, namely, the negative charge state of single nitrogen-vacancy defect centers (NV^{−} in diamond. We experimentally demonstrate, deterministic, purely electrical charge-state initialization of individual NV centers. The NV centers are placed in the intrinsic region of a p-i-n diode structure that facilitates the delivery of charge carriers to the defect for charge-state switching. The charge-state dynamics of a single NV center were investigated by time-resolved measurements and a nondestructive single-shot readout of the charge state. Fast charge-state switching rates (from negative to neutrally charged defects, which are greater than 0.72 ± 0.10  μs^{−1}, were realized. Furthermore, in no-operation mode, the realized charge states were stable for presumably much more than 0.45 s. We believe that the results obtained are useful not only for ultrafast electrical control of qubits, long T_{2} quantum memory, and quantum sensors associated with single NV centers but also for classical memory devices based on single atomic storage bits working under ambient conditions.

  19. Electroluminescence from charge transfer states in Donor/Acceptor solar cells

    DEFF Research Database (Denmark)

    Sherafatipour, Golenaz; Madsen, Morten

    Charge photocurrent generation is a key process in solar energy conversion systems. Effective dissociation of the photo-generated electron-hole pairs (excitons) has a strong influence on the efficiency of the organic solar cells. Charge dissociation takes place at the donor/acceptor interface via...... which the maximum open-circuit voltage can be estimated, and further can be used in the modeling and optimization of the OPV devices. [1] C. Deibe, T. Strobe, and V. Dyakonov, “Role of the charge transfer state in organic donor-acceptor solar cells,” Adv. Mater., vol. 22, pp. 4097–4111, 2010. [2] K...... charge transfer (CT) excitons, which is Coulombically bound interfacial electron- hole pairs residing at the donor/acceptor heterojunctions. The CT state represents an intermediate state between the exciton dissociation and recombination back to the ground state. Since the recombination of photo...

  20. Electronically shielded solid state charged particle detector

    International Nuclear Information System (INIS)

    Balmer, D.K.; Haverty, T.W.; Nordin, C.W.; Tyree, W.H.

    1996-01-01

    An electronically shielded solid state charged particle detector system having enhanced radio frequency interference immunity includes a detector housing with a detector entrance opening for receiving the charged particles. A charged particle detector having an active surface is disposed within the housing. The active surface faces toward the detector entrance opening for providing electrical signals representative of the received charged particles when the received charged particles are applied to the active surface. A conductive layer is disposed upon the active surface. In a preferred embodiment, a nonconductive layer is disposed between the conductive layer and the active surface. The conductive layer is electrically coupled to the detector housing to provide a substantially continuous conductive electrical shield surrounding the active surface. The inner surface of the detector housing is supplemented with a radio frequency absorbing material such as ferrite. 1 fig

  1. Higher-speed coronal mass ejections and their geoeffectiveness

    Science.gov (United States)

    Singh, A. K.; Bhargawa, Asheesh; Tonk, Apeksha

    2018-06-01

    We have attempted to examine the ability of coronal mass ejections to cause geoeffectiveness. To that end, we have investigated total 571 cases of higher-speed (> 1000 km/s) coronal mass ejection events observed during the years 1996-2012. On the basis of angular width (W) of observance, events of coronal mass ejection were further classified as front-side or halo coronal mass ejections (W = 360°); back-side halo coronal mass ejections (W = 360°); partial halo (120°mass ejections were much faster and more geoeffective in comparison of partial halo and non-halo coronal mass ejections. We also inferred that the front-sided halo coronal mass ejections were 67.1% geoeffective while geoeffectiveness of partial halo coronal mass ejections and non-halo coronal mass ejections were found to be 44.2% and 56.6% respectively. During the same period of observation, 43% of back-sided CMEs showed geoeffectiveness. We have also investigated some events of coronal mass ejections having speed > 2500 km/s as a case study. We have concluded that mere speed of coronal mass ejection and their association with solar flares or solar activity were not mere criterion for producing geoeffectiveness but angular width of coronal mass ejections and their originating position also played a key role.

  2. An equatorial coronal hole at solar minimum

    Science.gov (United States)

    Bromage, B. J. I.; DelZanna, G.; DeForest, C.; Thompson, B.; Clegg, J. R.

    1997-01-01

    The large transequatorial coronal hole that was observed in the solar corona at the end of August 1996 is presented. It consists of a north polar coronal hole called the 'elephant's trunk or tusk'. The observations of this coronal hole were carried out with the coronal diagnostic spectrometer onboard the Solar and Heliospheric Observatory (SOHO). The magnetic field associated with the equatorial coronal hole is strongly connected to that of the active region at its base, resulting in the two features rotating at almost the same rate.

  3. Controlled phase gate for solid-state charge-qubit architectures

    International Nuclear Information System (INIS)

    Schirmer, S.G.; Oi, D.K.L.; Greentree, Andrew D.

    2005-01-01

    We describe a mechanism for realizing a controlled phase gate for solid-state charge qubits. By augmenting the positionally defined qubit with an auxiliary state, and changing the charge distribution in the three-dot system, we are able to effectively switch the Coulombic interaction, effecting an entangling gate. We consider two architectures, and numerically investigate their robustness to gate noise

  4. Charge-state distribution measurements of ^{238}U and ^{136}Xe at 11  MeV/nucleon using gas charge stripper

    Directory of Open Access Journals (Sweden)

    H. Kuboki

    2010-09-01

    Full Text Available The charge-state distributions and equilibrium charge states of uranium (^{238}U and xenon (^{136}Xe ions at 11  MeV/nucleon were determined using a gas charge stripper. A differential pumping system facilitated the increase of the nitrogen gas thickness up to 1.3  mg/cm^{2}, which is sufficient for the most probable charge state to attain equilibrium. The charge states of ^{238}U attain equilibrium at 56.0, 56.6, and 55.7 in N_{2}, Ar, and CO_{2} media with thicknesses of 125, 79, and 126  μg/cm^{2}, respectively, while those of ^{136}Xe attain equilibrium at 40.5, 40.1, and 40.3 in N_{2}, Ar, and CO_{2} media with thicknesses of 163, 95, and 139  μg/cm^{2}, respectively. The equilibrium charge states of ^{136}Xe are acceptable for acceleration by the subsequent cyclotron. The measured data of ^{238}U were used to devise an empirical formula for the prediction of the equilibrium charge state in gaseous media over the energy region of 0.01–60  MeV/nucleon. The equilibrium charge state of ^{136}Xe as predicted by the devised formula is in good agreement with the data.

  5. Solar radio bursts of spectral type II, coronal shocks, and optical coronal transients

    Science.gov (United States)

    Maxwell, A.; Dryer, M.

    1981-01-01

    An examination is presented of the association of solar radio bursts of spectral type II and coronal shocks with solar flare ejecta observed in H-alpha, the green coronal line, and white-light coronagraphs. It is suggested that fast-moving optical coronal transients should for the most part be identified with piston-type phenomena well behind the outward-traveling shock waves that generate type II radio bursts. A general model is presented which relates type II radio bursts and coronal shocks to optically observed ejecta and consists of three main velocity regimes: (1) a quasi-hemispherical shock wave moving outward from the flare at speeds of 1000-2000 km/sec and Alfven Mach number of about 1.5; (2) the velocity of the piston driving the shock, on the order of 0.8 that of the shock; and (3) the regime of the slower-moving H-alpha ejecta, with velocities of 300-500 km/sec.

  6. Interpretation of coronal synoptic observations

    International Nuclear Information System (INIS)

    Munro, R.H.; Fisher, R.R.

    1986-01-01

    Three-dimensional reconstruction techniques used to determine coronal density distributions from synoptic data are complicated and time consuming to employ. Current techniques also assume time invariant structures and thus mix both temporal and spatial variations present in the coronal data. The observed distribution of polarized brightness, pB, and brightness, B, of coronal features observed either at eclipses or with coronagraphs depends upon both the three-dimensional distribution of electron density within the structure and the location of the feature with respect to the plane-of-the-sky. By theoretically studying the signature of various coronal structures as they would appear during a limb transit, it is possible to recognize these patterns in real synoptic data as well as estimate temporal evolutionary effects

  7. Remaking the medico-legal scene: a social history of the late-Victorian coroner in Oxford.

    Science.gov (United States)

    Hurren, Elizabeth T

    2010-04-01

    There have been wide-ranging debates about medicine and the law encapsulated in the figure of the coroner in Victorian England. Recently the historical literature on coroners has been enriched by macro-studies. Despite this important research, the social lives of coroners and their daily interactions remain relatively neglected in standard historical accounts. This article redresses that issue by examining the working life of the coroner for Oxford during the late-Victorian era. Edward Law Hussey kept very detailed records of his time in office as coroner. New research material makes it feasible to trace his professional background, from doctor of the sick poor, to hospital house surgeon and then busy coroner. His career trajectory, personal interactions, and professional disputes, provide an important historical prism illuminating contemporary debates that occupied coroners in their working lives. Hussey tried to improve his medico-legal reach and the public image of his coroner's office by reducing infanticide rates, converting a public mortuary, and acquiring a proper coroner's court. His campaigns had limited success because the social scene in which he worked was complicated by the dominance of health and welfare agencies that resented his role as an expanding arm of the Victorian information state.

  8. Resonance charge exchange between excited states in slow proton-hydrogen collisions

    International Nuclear Information System (INIS)

    Tolstikhina, Inga Yu.; Kato, Daiji

    2010-01-01

    The theory of resonance charge exchange in slow collisions of a proton with a hydrogen atom in the excited state is developed. It extends the Firsov-Demkov theory of resonance charge exchange to the case of degenerate initial and final states. The theory is illustrated by semiclassical and quantum calculations of charge exchange cross sections between states with n=2 in parabolic and spherical coordinates. The results are compared with existing close-coupling calculations.

  9. The Coronal Place; Why is It Special?

    Directory of Open Access Journals (Sweden)

    Azhar Alkazwini

    2017-10-01

    Full Text Available To prove the existence of arguments about the exact place that can bear the term ‘coronal’, it would be enough to check the explanatory dictionary’s entry. There are different arguments regarding the exact place of coronal. In this paper, some of the linguistic evidence regarding the coronal place shall be mentioned. Then, I shall discuss the classes of coronal that lend support to the fact that coronal place is believed to be special, and that is by discussing the different typologies of coronal consonants and giving their description.

  10. Charge state distribution of ^{86}Kr in hydrogen and helium gas charge strippers at 2.7  MeV/nucleon

    Directory of Open Access Journals (Sweden)

    H. Kuboki

    2014-12-01

    Full Text Available The charge state distributions of krypton (^{86}Kr with an energy of 2.7  MeV/nucleon were measured using hydrogen (H_{2} and helium (He gas charge strippers. A differential pumping system was constructed to confine H_{2} and He gases to a thickness sufficient for the charge state distributions to attain equilibrium. The mean charge states of ^{86}Kr in H_{2} and He gases attained equilibrium at 25.1 and 23.2, respectively, whereas the mean charge state in N_{2} gas at equilibrium was estimated to be less than 20. The charge distributions are successfully reproduced by the cross sections of ionization and electron capture processes optimized by a fitting procedure.

  11. FIELD TOPOLOGY ANALYSIS OF A LONG-LASTING CORONAL SIGMOID

    International Nuclear Information System (INIS)

    Savcheva, A. S.; Van Ballegooijen, A. A.; DeLuca, E. E.

    2012-01-01

    We present the first field topology analysis based on nonlinear force-free field (NLFFF) models of a long-lasting coronal sigmoid observed in 2007 February with the X-Ray Telescope on Hinode. The NLFFF models are built with the flux rope insertion method and give the three-dimensional coronal magnetic field as constrained by observed coronal loop structures and photospheric magnetograms. Based on these models, we have computed horizontal maps of the current and the squashing factor Q for 25 different heights in the corona for all six days of the evolution of the region. We use the squashing factor to quantify the degree of change of the field line linkage and to identify prominent quasi-separatrix layers (QSLs). We discuss the major properties of these QSL maps and devise a way to pick out important QSLs since our calculation cannot reach high values of Q. The complexity in the QSL maps reflects the high degree of fragmentation of the photospheric field. We find main QSLs and current concentrations that outline the flux rope cavity and that become characteristically S-shaped during the evolution of the sigmoid. We note that, although intermittent bald patches exist along the length of the sigmoid during its whole evolution, the flux rope remains stable for several days. However, shortly after the topology of the field exhibits hyperbolic flux tubes (HFT) on February 7 and February 12 the sigmoid loses equilibrium and produces two B-class flares and associated coronal mass ejections (CMEs). The location of the most elevated part of the HFT in our model coincides with the inferred locations of the two flares. Therefore, we suggest that the presence of an HFT in a coronal magnetic configuration may be an indication that the system is ready to erupt. We offer a scenario in which magnetic reconnection at the HFT drives the system toward the marginally stable state. Once this state is reached, loss of equilibrium occurs via the torus instability, producing a CME.

  12. MULTIDIMENSIONAL MODELING OF CORONAL RAIN DYNAMICS

    Energy Technology Data Exchange (ETDEWEB)

    Fang, X.; Xia, C.; Keppens, R. [Centre for mathematical Plasma Astrophysics, Department of Mathematics, KU Leuven, B-3001 Leuven (Belgium)

    2013-07-10

    We present the first multidimensional, magnetohydrodynamic simulations that capture the initial formation and long-term sustainment of the enigmatic coronal rain phenomenon. We demonstrate how thermal instability can induce a spectacular display of in situ forming blob-like condensations which then start their intimate ballet on top of initially linear force-free arcades. Our magnetic arcades host a chromospheric, transition region, and coronal plasma. Following coronal rain dynamics for over 80 minutes of physical time, we collect enough statistics to quantify blob widths, lengths, velocity distributions, and other characteristics which directly match modern observational knowledge. Our virtual coronal rain displays the deformation of blobs into V-shaped features, interactions of blobs due to mostly pressure-mediated levitations, and gives the first views of blobs that evaporate in situ or are siphoned over the apex of the background arcade. Our simulations pave the way for systematic surveys of coronal rain showers in true multidimensional settings to connect parameterized heating prescriptions with rain statistics, ultimately allowing us to quantify the coronal heating input.

  13. MULTIDIMENSIONAL MODELING OF CORONAL RAIN DYNAMICS

    International Nuclear Information System (INIS)

    Fang, X.; Xia, C.; Keppens, R.

    2013-01-01

    We present the first multidimensional, magnetohydrodynamic simulations that capture the initial formation and long-term sustainment of the enigmatic coronal rain phenomenon. We demonstrate how thermal instability can induce a spectacular display of in situ forming blob-like condensations which then start their intimate ballet on top of initially linear force-free arcades. Our magnetic arcades host a chromospheric, transition region, and coronal plasma. Following coronal rain dynamics for over 80 minutes of physical time, we collect enough statistics to quantify blob widths, lengths, velocity distributions, and other characteristics which directly match modern observational knowledge. Our virtual coronal rain displays the deformation of blobs into V-shaped features, interactions of blobs due to mostly pressure-mediated levitations, and gives the first views of blobs that evaporate in situ or are siphoned over the apex of the background arcade. Our simulations pave the way for systematic surveys of coronal rain showers in true multidimensional settings to connect parameterized heating prescriptions with rain statistics, ultimately allowing us to quantify the coronal heating input.

  14. Coronal magnetometry

    CERN Document Server

    Zhang, Jie; Bastian, Timothy

    2014-01-01

    This volume is a collection of research articles on the subject of the solar corona, and particularly, coronal magnetism. The book was motivated by the Workshop on Coronal Magnetism: Connecting Models to Data and the Corona to the Earth, which was held 21 - 23 May 2012 in Boulder, Colorado, USA. This workshop was attended by approximately 60 researchers. Articles from this meeting are contained in this topical issue, but the topical issue also contains contributions from researchers not present at the workshop. This volume is aimed at researchers and graduate students active in solar physics. Originally published in Solar Physics, Vol. 288, Issue 2, 2013 and Vol. 289, Issue 8, 2014.

  15. Charge-changing processes of heavy ions in matter. Non-equilibrium charge state distribution of sulfur ions after carbon foil penetration

    International Nuclear Information System (INIS)

    Imai, Makoto; Shibata, Hiromi; Sataka, Masao; Sugai, Hiroyuki; Nishio, Katsuhisa; Sugiyama, Koji; Komaki, Ken-ichiro

    2005-01-01

    Charge state distributions of 2.0 MeV/u (64 MeV) sulfur ions of various initial charge states (6+, 10+, 11+, 13+) after passing through 0.9, 1.1, 1.5, 2.0, 3.0, 4.7, 6.9 and 10 μg/cm 2 carbon foils have been studied experimentally using the heavy ion spectrometer 'ENMA'. Measured charge state distributions do not flat off to establish equilibrium within the measured thickness, proving to be the first systematic measurement of non-equilibrium charge state distribution using solid target at this energy range. The mean charge states and their distribution widths almost saturate to 12.4 and 1.03, respectively, for all initial charge states examined. Calculation with ETACHA code, developed by Rozet et al. [Nucl. Instr. and Meth. B 107 (1996) 67], is employed, although the present impact energy is lower than the assumed energy region for this code. It was also confirmed that a certain portion of 16 O q+ (q=3, 4, 7) beam is included in 32 S q+ (q=6, 8, 14) beam provided from the Tandem Accelerator, which originates in the Negative Ion Source forming O 2 - . (author)

  16. DIRECT OBSERVATION OF SOLAR CORONAL MAGNETIC FIELDS BY VECTOR TOMOGRAPHY OF THE CORONAL EMISSION LINE POLARIZATIONS

    International Nuclear Information System (INIS)

    Kramar, M.; Lin, H.; Tomczyk, S.

    2016-01-01

    We present the first direct “observation” of the global-scale, 3D coronal magnetic fields of Carrington Rotation (CR) Cycle 2112 using vector tomographic inversion techniques. The vector tomographic inversion uses measurements of the Fe xiii 10747 Å Hanle effect polarization signals by the Coronal Multichannel Polarimeter (CoMP) and 3D coronal density and temperature derived from scalar tomographic inversion of Solar Terrestrial Relations Observatory (STEREO)/Extreme Ultraviolet Imager (EUVI) coronal emission lines (CELs) intensity images as inputs to derive a coronal magnetic field model that best reproduces the observed polarization signals. While independent verifications of the vector tomography results cannot be performed, we compared the tomography inverted coronal magnetic fields with those constructed by magnetohydrodynamic (MHD) simulations based on observed photospheric magnetic fields of CR 2112 and 2113. We found that the MHD model for CR 2112 is qualitatively consistent with the tomography inverted result for most of the reconstruction domain except for several regions. Particularly, for one of the most noticeable regions, we found that the MHD simulation for CR 2113 predicted a model that more closely resembles the vector tomography inverted magnetic fields. In another case, our tomographic reconstruction predicted an open magnetic field at a region where a coronal hole can be seen directly from a STEREO-B/EUVI image. We discuss the utilities and limitations of the tomographic inversion technique, and present ideas for future developments

  17. Generation of cluster states with Josephson charge qubits

    International Nuclear Information System (INIS)

    Zheng, Xiao-Hu; Dong, Ping; Xue, Zheng-Yuan; Cao, Zhuo-Liang

    2007-01-01

    A scheme for the generation of the cluster states based on the Josephson charge qubits is proposed. The two-qubit generation case is introduced first, and then generalized to multi-qubit case. The successful probability and fidelity of current multi-qubit cluster state are both 1.0. The scheme is simple and can be easily manipulated, because any two charge qubits can be selectively and effectively coupled by a common inductance. More manipulations can be realized before decoherence sets in. All the devices in the scheme are well within the current technology

  18. Equilibrium charge state distributions of high energy heavy ions

    International Nuclear Information System (INIS)

    Clark, R.B.; Grant, I.S.; King, R.; Eastham, D.A.; Joy, T.

    1976-01-01

    Equilibrium charge state fractions have been measured for N, O, Ne, S, Ar and Kr ions at 1.04 MeV/nucleon after passing through various stripping materials. Further data were obtained at higher energy for S ions (4.12 MeV/nucleon) and Ar ions (4.12 and 9.6 MeV/nucleon). The mean charge fractions can be fitted to universal curves for both solid and gaseous strippers. Measurements of the equilibrium fraction of krypton ions at 1.04 MeV/nucleon passing through heavy vapours have shown that a higher average charge state is obtained than for lighter gaseous strippers. (Auth.)

  19. Theoretical Study of the Charge-Transfer State Separation within Marcus Theory

    DEFF Research Database (Denmark)

    Volpi, Riccardo; Nassau, Racine; Nørby, Morten Steen

    2016-01-01

    We study, within Marcus theory, the possibility of the charge-transfer (CT) state splitting at organic interfaces and a subsequent transport of the free charge carriers to the electrodes. As a case study we analyze model anthracene-C60 interfaces. Kinetic Monte Carlo (KMC) simulations on the cold...... CT state were performed at a range of applied electric fields, and with the fields applied at a range of angles to the interface to simulate the action of the electric field in a bulk heterojunction (BHJ) interface. The results show that the inclusion of polarization in our model increases CT state...... dissociation and charge collection. The effect of the electric field on CT state splitting and free charge carrier conduction is analyzed in detail with and without polarization. Also, depending on the relative orientation of the anthracene and C60 molecules at the interface, CT state splitting shows different...

  20. The dynamics of coronal magnetic structures

    International Nuclear Information System (INIS)

    Weber, W.

    1978-01-01

    An analysis is made of the evolution of coronal magnetic fields due to the interaction with the solar wind. An analysis of the formation of coronal streamers, arising as a result of the stretching of bipolar fields, is given. Numerical simulations of the formation of coronal streamers are presented. Fast-mode shocks as triggers of microturbulence in the solar corona are discussed

  1. Evolving Coronal Holes and Interplanetary Erupting Stream ...

    Indian Academy of Sciences (India)

    prominences, have a significantly higher rate of occurrence in the vicinity of coronal .... coronal holes due to the birth of new holes or the growth of existing holes. .... Statistics of newly formed coronal hole areas (NFOCHA) associated with ...

  2. Charge-transfer cross sections in collisions of ground-state Ca and H+

    Science.gov (United States)

    Dutta, C. M.; Oubre, C.; Nordlander, P.; Kimura, M.; Dalgarno, A.

    2006-03-01

    We have investigated collisions of Ca(4s2) with H+ in the energy range of 200eV/u-10keV/u using the semiclassical molecular-orbital close-coupling (MOCC) method with 18 coupled molecular states ( 11Σ+1 and seven Π+1 states) to determine charge-transfer cross sections. Except for the incoming channel 6Σ+1 , the molecular states all correspond to charge-transfer channels. Inclusion of Ca2+-H- is crucial in the configuration-interaction calculation for generating the molecular wave functions and potentials. Because of the Coulomb attraction, the state separating to Ca2+-H- creates many avoided crossings, even though at infinite separation it lies energetically above all other states that we included. Because of the avoided crossings between the incoming channel 6Σ+1 and the energetically close charge-transfer channel 7Σ+1 the charge-transfer interaction occurs at long range. This makes calculations of charge-transfer cross sections by the MOCC method very challenging. The total charge-transfer cross sections increase monotonically from 3.4×10-15cm2 at 200eV/u to 4.5×10-15cm2 at 10keV/u . Charge transfer occurs mostly to the excited Ca+(5p) state in the entire energy range, which is the sum of the charge transfer to 7Σ+1 and 4Π+1 . It accounts for ˜47% of the total charge transfer cross sections at 200eV/u . However, as the energy increases, transfer to Ca+(4d) increases, and at 10keV/u the charge-transfer cross sections for Ca+(5p) and Ca+(4d) become comparable, each giving ˜38% of the total cross section.

  3. Charge-transfer cross sections in collisions of ground-state Ca and H+

    International Nuclear Information System (INIS)

    Dutta, C. M.; Oubre, C.; Nordlander, P.; Kimura, M.; Dalgarno, A.

    2006-01-01

    We have investigated collisions of Ca(4s 2 ) with H + in the energy range of 200 eV/u-10 keV/u using the semiclassical molecular-orbital close-coupling (MOCC) method with 18 coupled molecular states (11 1 Σ + and seven 1 Π + states) to determine charge-transfer cross sections. Except for the incoming channel 6 1 Σ + , the molecular states all correspond to charge-transfer channels. Inclusion of Ca 2+ -H - is crucial in the configuration-interaction calculation for generating the molecular wave functions and potentials. Because of the Coulomb attraction, the state separating to Ca 2+ -H - creates many avoided crossings, even though at infinite separation it lies energetically above all other states that we included. Because of the avoided crossings between the incoming channel 6 1 Σ + and the energetically close charge-transfer channel 7 1 Σ + the charge-transfer interaction occurs at long range. This makes calculations of charge-transfer cross sections by the MOCC method very challenging. The total charge-transfer cross sections increase monotonically from 3.4x10 -15 cm 2 at 200 eV/u to 4.5x10 -15 cm 2 at 10 keV/u. Charge transfer occurs mostly to the excited Ca + (5p) state in the entire energy range, which is the sum of the charge transfer to 7 1 Σ + and 4 1 Π + . It accounts for ∼47% of the total charge transfer cross sections at 200 eV/u. However, as the energy increases, transfer to Ca + (4d) increases, and at 10 keV/u the charge-transfer cross sections for Ca + (5p) and Ca + (4d) become comparable, each giving ∼38% of the total cross section

  4. Solid state cloaking for electrical charge carrier mobility control

    Science.gov (United States)

    Zebarjadi, Mona; Liao, Bolin; Esfarjani, Keivan; Chen, Gang

    2015-07-07

    An electrical mobility-controlled material includes a solid state host material having a controllable Fermi energy level and electrical charge carriers with a charge carrier mobility. At least one Fermi level energy at which a peak in charge carrier mobility is to occur is prespecified for the host material. A plurality of particles are distributed in the host material, with at least one particle disposed with an effective mass and a radius that minimize scattering of the electrical charge carriers for the at least one prespecified Fermi level energy of peak charge carrier mobility. The minimized scattering of electrical charge carriers produces the peak charge carrier mobility only at the at least one prespecified Fermi level energy, set by the particle effective mass and radius, the charge carrier mobility being less than the peak charge carrier mobility at Fermi level energies other than the at least one prespecified Fermi level energy.

  5. Nickel-Hydrogen Battery Fault Clearing at Low State of Charge

    Science.gov (United States)

    Lurie, C.

    1997-01-01

    Fault clearing currents were achieved and maintained at discharge rates from C/2 to C/3 at high and low states of charge. The fault clearing plateau voltage is strong function of: discharge current, and voltage-prior-to-the-fault-clearing-event and a weak function of state of charge. Voltage performance, for the range of conditions reported, is summarized.

  6. Charge state distributions for heavy ions in carbon stripper foils

    International Nuclear Information System (INIS)

    McMahan, M.A.; Lebed, R.F.; Feinberg, B.

    1989-03-01

    We have extended the database of measured charge state distributions available in the literature through measurements at the SuperHILAC using carbon stripper foils in the energy range 1.2--8.5 MeV/u. Modifying a semi-empirical model to include the effect of electronic shells, we are able to correctly predict the mean charge state to within 1/2 a charge state for 6≤Z≤92 and energies from 30 keV/u to 16 MeV/u. We have determined parameters for the widths of the distributions for each electronic shell. For distributions lying across a shell boundary, we join the two Gaussians of different widths to get an asymmetric distribution. 18 refs., 4 figs., 2 tabs

  7. Manipulating quantum coherence of charge states in interacting double-dot Aharonov–Bohm interferometers

    Science.gov (United States)

    Jin, Jinshuang; Wang, Shikuan; Zhou, Jiahuan; Zhang, Wei-Min; Yan, YiJing

    2018-04-01

    We investigate the dynamics of charge-state coherence in a degenerate double-dot Aharonov–Bohm interferometer with finite inter-dot Coulomb interactions. The quantum coherence of the charge states is found to be sensitive to the transport setup configurations, involving both the single-electron impurity channels and the Coulomb-assisted ones. We numerically demonstrate the emergence of a complete coherence between the two charge states, with the relative phase being continuously controllable through the magnetic flux. Interestingly, a fully coherent charge qubit arises at the double-dots electron pair tunneling resonance condition, where the chemical potential of one electrode is tuned at the center between a single-electron impurity channel and the related Coulomb-assisted channel. This pure quantum state of charge qubit could be experimentally realized at the current–voltage characteristic turnover position, where differential conductance sign changes. We further elaborate the underlying mechanism for both the real-time and the stationary charge-states coherence in the double-dot systems of study.

  8. Excited state populations and charge-exchange of fast ions in solids

    International Nuclear Information System (INIS)

    Miller, P.D.; Sofield, C.J.; Woods, C.J.

    1984-01-01

    Excited state populations and charge state fractions of 445 MeV Cl ions have been measured for a range of thicknesses of solid C targets. Cross sections for electron capture, loss, excitation and excited state quenching have been determined and these data are found to predict a quantitative difference between equilibrium charge state distributions from gases and solids for a special case of the Bohr-Lindhard density effect model. 8 references, 1 figure, 1 table

  9. An EBIS for charge state breeding in the SPES project

    International Nuclear Information System (INIS)

    Variale, V.; Lamanna, G.; Valentino, V.; Brautti, G.; Clauser, T.; Raino, A.; Stagno, V.; Boggia, A.; Boimelshtein, Y.; Logatchov, P.; Skarbo, B.; Tiunov, M.

    2002-01-01

    The charge state breeder BRIC (Breeding Ion Charge) is in construction at the INFN section of Bari (Italy). It is based on EBIS scheme and it is designed to accept radioactive ion beam (RIB) with charge state +1 in a slow injection mode. This experiment can be considered as a first step towards the design and construction of a charge breeder for the SPES project. The new feature of BRIC, with respect to the classical EBIS is given by the insertion, in the ion chamber, of a rf-quadrupole aiming at filtering the unwanted masses and then making a more efficient containment of the wanted ions. In this paper, the breeder design, the simulation results of the electron and ion beam propagation and the construction problems of the device will be reported. (author)

  10. PONDEROMOTIVE ACCELERATION IN CORONAL LOOPS

    International Nuclear Information System (INIS)

    Dahlburg, R. B.; Obenschain, K.; Laming, J. M.; Taylor, B. D.

    2016-01-01

    Ponderomotive acceleration has been asserted to be a cause of the first ionization potential (FIP) effect, the well-known enhancement in abundance by a factor of 3–4 over photospheric values of elements in the solar corona with FIP less than about 10 eV. It is shown here by means of numerical simulations that ponderomotive acceleration occurs in solar coronal loops, with the appropriate magnitude and direction, as a “by-product” of coronal heating. The numerical simulations are performed with the HYPERION code, which solves the fully compressible three-dimensional magnetohydrodynamic equations including nonlinear thermal conduction and optically thin radiation. Numerical simulations of coronal loops with an axial magnetic field from 0.005 to 0.02 T and lengths from 25,000 to 75,000 km are presented. In the simulations the footpoints of the axial loop magnetic field are convected by random, large-scale motions. There is a continuous formation and dissipation of field-aligned current sheets, which act to heat the loop. As a consequence of coronal magnetic reconnection, small-scale, high-speed jets form. The familiar vortex quadrupoles form at reconnection sites. Between the magnetic footpoints and the corona the reconnection flow merges with the boundary flow. It is in this region that the ponderomotive acceleration occurs. Mirroring the character of the coronal reconnection, the ponderomotive acceleration is also found to be intermittent.

  11. PONDEROMOTIVE ACCELERATION IN CORONAL LOOPS

    Energy Technology Data Exchange (ETDEWEB)

    Dahlburg, R. B.; Obenschain, K. [LCP and FD, Naval Research Laboratory, Washington, DC 20375 (United States); Laming, J. M. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Taylor, B. D. [AFRL Eglin AFB, Pensacola, FL 32542 (United States)

    2016-11-10

    Ponderomotive acceleration has been asserted to be a cause of the first ionization potential (FIP) effect, the well-known enhancement in abundance by a factor of 3–4 over photospheric values of elements in the solar corona with FIP less than about 10 eV. It is shown here by means of numerical simulations that ponderomotive acceleration occurs in solar coronal loops, with the appropriate magnitude and direction, as a “by-product” of coronal heating. The numerical simulations are performed with the HYPERION code, which solves the fully compressible three-dimensional magnetohydrodynamic equations including nonlinear thermal conduction and optically thin radiation. Numerical simulations of coronal loops with an axial magnetic field from 0.005 to 0.02 T and lengths from 25,000 to 75,000 km are presented. In the simulations the footpoints of the axial loop magnetic field are convected by random, large-scale motions. There is a continuous formation and dissipation of field-aligned current sheets, which act to heat the loop. As a consequence of coronal magnetic reconnection, small-scale, high-speed jets form. The familiar vortex quadrupoles form at reconnection sites. Between the magnetic footpoints and the corona the reconnection flow merges with the boundary flow. It is in this region that the ponderomotive acceleration occurs. Mirroring the character of the coronal reconnection, the ponderomotive acceleration is also found to be intermittent.

  12. Coronal Heating: Testing Models of Coronal Heating by Forward-Modeling the AIA Emission of the Ansample of Coronal Loops

    Science.gov (United States)

    Malanushenko, A. V.

    2015-12-01

    We present a systemic exploration of the properties of coronal heating, by forward-modeling the emission of the ensemble of 1D quasi-steady loops. This approximations were used in many theoretical models of the coronal heating. The latter is described in many such models in the form of power laws, relating heat flux through the photosphere or volumetric heating to the strength of the magnetic field and length of a given field line. We perform a large search in the parameter space of these power laws, amongst other variables, and compare the resulting emission of the active region to that observed by AIA. We use a recently developed magnetic field model which uses shapes of coronal loops to guide the magnetic model; the result closely resembles observed structures by design. We take advantage of this, by comparing, in individual sub-regions of the active region, the emission of the active region and its synthetic model. This study allows us to rule out many theoretical models and formulate predictions for the heating models to come.

  13. AARHUS: Exotic charge states in ASTRID

    International Nuclear Information System (INIS)

    Moller, Soren Pape

    1995-01-01

    Ions are atoms from which one or more orbital electrons have been detached. This removal can be done, for example, by impact of other electrons. Today beams of bare ions - nuclei without any electrons - are available, for example at the GSI heavy ion Laboratory, Darmstadt, even for the heaviest elements. Molecules too can be ionized by removal of one electron and these molecules can be accelerated to form high energy beams. Molecules are, however, generally not expected to be stable when more than one electron is missing, since there is too little negative charge to bind the positive nuclei. It was therefore a surprise when a stable doubly-charged molecular ion was found at experiments at the ASTRID storage ring, Aarhus, Denmark. The aim of the experiment was to measure lifetimes of expected metastable states of doubly-charged carbon monoxide, CO ++ . The CO ++ ions were produced in an ion source and the accelerated beam injected into the storage ring. The circulating intensity was then monitored by detecting neutral species produced in restgas collisions at the end of a straight section. For CO ++ , a fraction of the beam survived for tens of seconds, with a lifetime around 4 seconds. This lifetime was dominated by restgas collisions. The base pressure was around 2 x 10 -11 mbar. In order to avoid contamination from molecules with the same mass/charge ratio, e.g. singly-charged nitrogen-14, the carbon monoxide used was based on the naturally rare isotope carbon-13 rather than the abundant carbon-12. Many atoms can also bind an additional electron and form negative ions. Several negative ions are metastable, and lifetime measurements performed at ASTRID and elsewhere produce accurate results important for comparisons with theory. Double-charged negative ions could in principle exist, and indications of metastable states of H - and O - were seen some years ago as resonances in the electron bombardment of negative hydrogen ions. This process was recently studied at

  14. AARHUS: Exotic charge states in ASTRID

    Energy Technology Data Exchange (ETDEWEB)

    Moller, Soren Pape

    1995-04-15

    Ions are atoms from which one or more orbital electrons have been detached. This removal can be done, for example, by impact of other electrons. Today beams of bare ions - nuclei without any electrons - are available, for example at the GSI heavy ion Laboratory, Darmstadt, even for the heaviest elements. Molecules too can be ionized by removal of one electron and these molecules can be accelerated to form high energy beams. Molecules are, however, generally not expected to be stable when more than one electron is missing, since there is too little negative charge to bind the positive nuclei. It was therefore a surprise when a stable doubly-charged molecular ion was found at experiments at the ASTRID storage ring, Aarhus, Denmark. The aim of the experiment was to measure lifetimes of expected metastable states of doubly-charged carbon monoxide, CO{sup ++}. The CO{sup ++} ions were produced in an ion source and the accelerated beam injected into the storage ring. The circulating intensity was then monitored by detecting neutral species produced in restgas collisions at the end of a straight section. For CO{sup ++}, a fraction of the beam survived for tens of seconds, with a lifetime around 4 seconds. This lifetime was dominated by restgas collisions. The base pressure was around 2 x 10{sup -11} mbar. In order to avoid contamination from molecules with the same mass/charge ratio, e.g. singly-charged nitrogen-14, the carbon monoxide used was based on the naturally rare isotope carbon-13 rather than the abundant carbon-12. Many atoms can also bind an additional electron and form negative ions. Several negative ions are metastable, and lifetime measurements performed at ASTRID and elsewhere produce accurate results important for comparisons with theory. Double-charged negative ions could in principle exist, and indications of metastable states of H{sup -} and O{sup -} were seen some years ago as resonances in the electron bombardment of negative hydrogen ions. This

  15. A high charge state heavy ion beam source for heavy ion fusion

    International Nuclear Information System (INIS)

    Eylon, S.; Henestroza, E.

    1996-01-01

    A high current, low emittance, high charge state heavy ion beam source is being developed. This is designed to deliver a heavy ion fusion (HIF) driver accelerator scale beam. Using a high charge state beam in a driver accelerator for HIF may increase the acceleration efficiency, leading to a reduction in the driver accelerator size and cost. The proposed source system, which consists of a gas beam electron stripper followed by a high charge state beam separator, can be added to existing single charge state, low emittance, high brightness ion sources and injectors. We shall report on the source physics design using 3D beam simulations and experimental feasibility study results using a neutral gas stripper and a beam separator at the exit of the LBL 2 MV injector. (orig.)

  16. Vacuum arc ion charge state distributions

    International Nuclear Information System (INIS)

    Brown, I.G.; Godechot, X.

    1990-06-01

    We have measured vacuum arc ion charge state spectra for a wide range of metallic cathode materials. The charge state distributions were measured using a time-of-flight diagnostic to monitor the energetic ion beam produced by a metal vapor vacuum arc ion source. We have obtained data for 48 metallic cathode elements: Li, C, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ge, Sr, Y, Zr, Nb, Mo, Pd, Ag, Cd, In, Sn, Ba, La, Ce, Pr, Nd, Sm, Gd, Dy, Ho, Er, Yb, Hf, Ta, W, Ir, Pt, Au, Pb, Bi, Th and U. The arc was operated in a pulsed mode with pulse length 0.25 msec; arc current was 100 A throughout. This array of elements extends and completes previous work by us. In this paper the measured distributions are cataloged and compared with our earlier results and with those of other workers. We also make some observations about the performance of the various elements as suitable vacuum arc cathode materials

  17. Vacuum arc ion charge-state distributions

    International Nuclear Information System (INIS)

    Brown, I.G.; Godechot, X.

    1991-01-01

    The authors have measured vacuum arc ion charge-state spectra for a wide range of metallic cathode materials. The charge-state distributions were measured using a time-of-flight diagnostic to monitor the energetic ion beam produced by a metal vapor vacuum arc ion source. They have obtained data for 48 metallic cathode elements: Li, C, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ge, Sr, Y, Zr, Nb, Mo, Pd, Ag, Cd, In, Sn, Ba, La, Ce, Pr, Nd, Sm, Gd, Dy, Ho, Er, Yb, Hf, Ta, W, Ir, Pt, Au, Pb, Bi, Th, and U. The arc was operated in a pulsed mode with pulse length 0.25 ms; arc current was 100 A throughout. This array of elements extends and completes previous work by the authors. In this paper the measured distributions are cataloged and compared with their earlier results and those of other workers. They also make some observations about the performance of the various elements as suitable vacuum arc cathode materials

  18. Critical Magnetic Field Strengths for Unipolar Solar Coronal Plumes In Quiet Regions and Coronal Holes?

    Science.gov (United States)

    Avallone, Ellis; Tiwari, Sanjiv K.; Panesar, Navdeep K.; Moore, Ronald L.; Winebarger, Amy

    2017-01-01

    Coronal plumes are bright magnetic funnels that are found in quiet regions and coronal holes that extend high into the solar corona whose lifetimes can last from hours to days. The heating processes that make plumes bright involve the magnetic field at the base of the plume, but their intricacies remain mysterious. Raouafi et al. (2014) infer from observation that plume heating is a consequence of magnetic reconnection at the base, whereas Wang et al. (2016) infer that plume heating is a result of convergence of the magnetic flux at the plume's base, or base flux. Both papers suggest that the base flux in their plumes is of mixed polarity, but do not quantitatively measure the base flux or consider whether a critical magnetic field strength is required for plume production. To investigate the magnetic origins of plume heating, we track plume luminosity in the 171 Å wavelength as well as the abundance and strength of the base flux over the lifetimes of six unipolar coronal plumes. Of these, three are in coronal holes and three are in quiet regions. For this sample, we find that plume heating is triggered when convergence of the base flux surpasses a field strength of approximately 300 - 500 Gauss, and that the luminosity of both quiet region and coronal hole plumes respond similarly to the strength of the magnetic field in the base.

  19. Abnormal Multiple Charge Memory States in Exfoliated Few-Layer WSe2 Transistors.

    Science.gov (United States)

    Chen, Mikai; Wang, Yifan; Shepherd, Nathan; Huard, Chad; Zhou, Jiantao; Guo, L J; Lu, Wei; Liang, Xiaogan

    2017-01-24

    To construct reliable nanoelectronic devices based on emerging 2D layered semiconductors, we need to understand the charge-trapping processes in such devices. Additionally, the identified charge-trapping schemes in such layered materials could be further exploited to make multibit (or highly desirable analog-tunable) memory devices. Here, we present a study on the abnormal charge-trapping or memory characteristics of few-layer WSe 2 transistors. This work shows that multiple charge-trapping states with large extrema spacing, long retention time, and analog tunability can be excited in the transistors made from mechanically exfoliated few-layer WSe 2 flakes, whereas they cannot be generated in widely studied few-layer MoS 2 transistors. Such charge-trapping characteristics of WSe 2 transistors are attributed to the exfoliation-induced interlayer deformation on the cleaved surfaces of few-layer WSe 2 flakes, which can spontaneously form ambipolar charge-trapping sites. Our additional results from surface characterization, charge-retention characterization at different temperatures, and density functional theory computation strongly support this explanation. Furthermore, our research also demonstrates that the charge-trapping states excited in multiple transistors can be calibrated into consistent multibit data storage levels. This work advances the understanding of the charge memory mechanisms in layered semiconductors, and the observed charge-trapping states could be further studied for enabling ultralow-cost multibit analog memory devices.

  20. Determination of Coronal Magnetic Fields from Vector Magnetograms

    Science.gov (United States)

    Mikic, Zoran

    1997-01-01

    During the course of the present contract we developed an 'evolutionary technique' for the determination of force-free coronal magnetic fields from vector magnetograph observations. The method can successfully generate nonlinear force- free fields (with non-constant-a) that match vector magnetograms. We demonstrated that it is possible to determine coronal magnetic fields from photospheric measurements, and we applied it to vector magnetograms of active regions. We have also studied theoretical models of coronal fields that lead to disruptions. Specifically, we have demonstrated that the determination of force-free fields from exact boundary data is a well-posed mathematical problem, by verifying that the computed coronal field agrees with an analytic force-free field when boundary data for the analytic field are used; demonstrated that it is possible to determine active-region coronal magnetic fields from photospheric measurements, by computing the coronal field above active region 5747 on 20 October 1989, AR6919 on 15 November 1991, and AR7260 on 18 August 1992, from data taken with the Stokes Polarimeter at Mees Solar Observatory, University of Hawaii; started to analyze active region 7201 on 19 June 1992 using measurements made with the Advanced Stokes Polarimeter at NSO/Sac Peak; investigated the effects of imperfections in the photospheric data on the computed coronal magnetic field; documented the coronal field structure of AR5747 and compared it to the morphology of footpoint emission in a flare, showing that the 'high- pressure' H-alpha footpoints are connected by coronal field lines; shown that the variation of magnetic field strength along current-carrying field lines is significantly different from the variation in a potential field, and that the resulting near-constant area of elementary flux tubes is consistent with observations; begun to develop realistic models of coronal fields which can be used to study flare trigger mechanisms; demonstrated that

  1. X-ray spectroscopy: An experimental technique to measure charge state distribution during ion–solid interaction

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Prashant, E-mail: prashant@iuac.res.in; Nandi, Tapan

    2016-01-08

    Charge state distributions of {sup 56}Fe and {sup 58}Ni projectile ions passing through thin carbon foils have been studied in the energy range of 1.65–2.69 MeV/u using a novel method involving the X-ray spectroscopy technique. Interestingly the charge state distribution in the bulk shows Lorentzian behavior instead of usual Gaussian distribution. Further, different parameters of charge state distribution like mean charge state, distribution width and asymmetric parameter are determined and compared with the empirical calculations and ETACHA predictions. It is found that the X-ray measurement technique is appropriate to determine the mean charge state during the ion–solid interaction or in the bulk. Interestingly, empirical formalism predicts much lower mean charge states of the projectile ions compared to X-ray measurements which clearly indicate multi-electron capture from the target surface. The ETACHA predictions and experimental results are found to be comparable for the present energy regime. - Highlights: • New method is proposed to determine charge state distribution using X-ray technique. • Charge state distribution parameters are calculated and compared with various theoretical predictions. • X-ray technique is found to be appropriate to segregate the charge state distribution in the bulk from the target surface. • ETACHA predictions are found satisfactory in the energy range of ≥1.65 MeV/u.

  2. An EBIS for charge state breeding in the SPES project

    Indian Academy of Sciences (India)

    development and testing of a charge state breeder device based on an EBIS source ... the number of particles that can be accumulated in a Penning source is limited. ... accounting for the magnetic field and the electron beam space charge.

  3. Modulation of nitrogen vacancy charge state and fluorescence in nanodiamonds using electrochemical potential.

    Science.gov (United States)

    Karaveli, Sinan; Gaathon, Ophir; Wolcott, Abraham; Sakakibara, Reyu; Shemesh, Or A; Peterka, Darcy S; Boyden, Edward S; Owen, Jonathan S; Yuste, Rafael; Englund, Dirk

    2016-04-12

    The negatively charged nitrogen vacancy (NV(-)) center in diamond has attracted strong interest for a wide range of sensing and quantum information processing applications. To this end, recent work has focused on controlling the NV charge state, whose stability strongly depends on its electrostatic environment. Here, we demonstrate that the charge state and fluorescence dynamics of single NV centers in nanodiamonds with different surface terminations can be controlled by an externally applied potential difference in an electrochemical cell. The voltage dependence of the NV charge state can be used to stabilize the NV(-) state for spin-based sensing protocols and provides a method of charge state-dependent fluorescence sensing of electrochemical potentials. We detect clear NV fluorescence modulation for voltage changes down to 100 mV, with a single NV and down to 20 mV with multiple NV centers in a wide-field imaging mode. These results suggest that NV centers in nanodiamonds could enable parallel optical detection of biologically relevant electrochemical potentials.

  4. Modulation of nitrogen vacancy charge state and fluorescence in nanodiamonds using electrochemical potential

    Science.gov (United States)

    Karaveli, Sinan; Gaathon, Ophir; Wolcott, Abraham; Sakakibara, Reyu; Shemesh, Or A.; Peterka, Darcy S.; Boyden, Edward S.; Owen, Jonathan S.; Yuste, Rafael; Englund, Dirk

    2016-04-01

    The negatively charged nitrogen vacancy (NV-) center in diamond has attracted strong interest for a wide range of sensing and quantum information processing applications. To this end, recent work has focused on controlling the NV charge state, whose stability strongly depends on its electrostatic environment. Here, we demonstrate that the charge state and fluorescence dynamics of single NV centers in nanodiamonds with different surface terminations can be controlled by an externally applied potential difference in an electrochemical cell. The voltage dependence of the NV charge state can be used to stabilize the NV- state for spin-based sensing protocols and provides a method of charge state-dependent fluorescence sensing of electrochemical potentials. We detect clear NV fluorescence modulation for voltage changes down to 100 mV, with a single NV and down to 20 mV with multiple NV centers in a wide-field imaging mode. These results suggest that NV centers in nanodiamonds could enable parallel optical detection of biologically relevant electrochemical potentials.

  5. Nickel-hydrogen battery state of charge management in the absence of active cooling

    Energy Technology Data Exchange (ETDEWEB)

    Lurie, C.; Foroozan, S. [TRW, Redondo Beach, CA (United States); Brewer, J.; Jackson, L.G. [NASA, Huntsville, AL (United States). Marshall Space Flight Center

    1995-12-31

    Battery management during prelaunch activities has always required special attention and careful planning. `ne transition from nickel-cadmium to nickel-hydrogen batteries, with their higher self discharge rate and lower charge efficiency, as well as longer prelaunch scenarios, have made this aspect of spacecraft management even more challenging. The NASA AXAF-I Program requires high battery state of charge at launch. The use of active cooling, to ensure adequate state of charge during prelaunch charge, trickle charge, and stand was considered and proved to be expensive and difficult to implement. Alternate approaches were considered. A procedure including optimized charging and low rate (charging, in the absence of active cooling, appeared promising and was investigated. The investigation includes three phases: (1) demonstration of the feasibility of the proposed procedure (2) development of a parametric data base (3) validation in an AXAF-I mission simulation test. Charging, trickle charging, and open circuit stand are considered in each phase. The major conclusion of this work is that nickel-hydrogen batteries can achieve and maintain high states of charge, in the absence of active cooling, using the approach described in this paper.

  6. Charge state analysis of heavy ions after penetration of uncleaned and sputter cleaned conducting surfaces

    International Nuclear Information System (INIS)

    Jung, M.; Schosnig, M.; Kroneberger, K.; Tobisch, M.; Maier, R.; Kuzel, M.; Fiedler, C.; Hofmann, D.; Groeneveld, K.O.

    1994-01-01

    The evolution of the charge state distribution of fast ions inside a solid is of basic interest in various research fields as stopping power measurements etc. The existing models for the charge state evolution differ in the treatment of the projectile-exit-surface interaction, which has a strong influence on the final charge state distributions. We measured the charge state distributions for C + , N + , and O + (30≤E/M≤130 keV/u) impact on thin C, Cu, and Au foils, where the surface properties were modified by sputter cleaning. The mesurements show a pronounced change of the mean projectile charge state to lower values in the case of sputter cleaned surfaces. This result underlines the importance of the projectile-surface interaction for the generation of the outcoming charge state distribution. (orig.)

  7. Charge-state distribution of MeV He ions scattered from the surface atoms

    International Nuclear Information System (INIS)

    Kimura, Kenji; Ohtsuka, Hisashi; Mannami, Michihiko

    1993-01-01

    The charge-state distribution of 500-keV He ions scattered from a SnTe (001) surface has been investigated using a new technique of high-resolution high-energy ion scattering spectroscopy. The observed charge-state distribution of ions scattered from the topmost atomic layer coincides with that of ions scattered from the subsurface region and does not depend on the incident charge state but depends on the exit angle. The observed exit-angle dependence is explained by a model which includes the charge-exchange process with the valence electrons in the tail of the electron distribution at the surface. (author)

  8. Electron capture into excited states of multi-charged ions

    International Nuclear Information System (INIS)

    Dijkkamp, D.

    1985-01-01

    This thesis deals with charge exchange reactions in slow collisions of multi-charged ions with neutral atoms or molecules. These reactions proceed very efficiently via a curve crossing mechanism, which leads to preferential population of excited states of the ion. The subsequent decay of these states leads to the emission of characteristic radiation. From wavelength resolved measurements of the absolute intensity of this radiation, cross sections for selective population of the excited (n,l-) states of the ion were determined. In addition, for some systems the total capture cross section was measured directly by means of charge state analysis of the secondary projectile ions. The role of charge exchange processes in fusion plasmas and in astrophysical plasmas is indicated. An experimental set-up is described with emphasis on the Electron Cyclotron Resonance Ion Source that was used in the experiments. Results for collisions of C 6+ , N 6+ , O 6+ and Ne 6+ with He, H 2 and Ar are presented as well as for electron capture from Li atoms by C 4+ and He 2+ . The interaction of the iso-electronic sequence C 4+ , N 5+ , O 6+ with atomic hydrogen, molecular hydrogen and helium is studied. First results for partial and total cross sections in collisions of fully stripped carbon, nitrogen and oxygen ions with atomic hydrogen are presented. These data are of particular importance for applications in fusion diagnostics. The data indicate that calculations of both molecular and atomic orbital type yield correct results, if an extended basis set is used. (Auth.)

  9. Vacuum improvements for ultra high charge state ion acceleration

    International Nuclear Information System (INIS)

    Xie, Z.Q.; Lyneis, C.M.; Clark, D.J.; Guy, A.; Lundgren, S.A

    1998-06-01

    The installation of a second cryo panel has significantly improved the vacuum in the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory. The neutral pressure in the extraction region decreased from 1.2 x 10 -6 down to about 7 x 10 -7 Torr. The vacuum improvement reduces beam loss from charge changing collisions and enhances the cyclotron beam transmission, especially for the high charge state heavy ions. Tests with improved vacuum show the cyclotron transmission increased more than 50% (from 5.7% to 9.0%) for a Xe 27+ at 603 MeV, more than doubled for a Bi 41+ beam (from 1.9% to 4.6%) at 904 MeV and tripled for a U 47+ beam (from 1.2% to 3.6%) at 1,115 MeV. At about 5 NeV/nucleon 92 enA (2.2 pnA) for Bi 41+ and 14 enA (0.3 pnA) for U 47+ were extracted ut of the 88-Inch Cyclotron Ion beams with charge states as high as U 64+ have been produced by the LBNL AECR-U ion source and accelerated through the cyclotron for the first time. The beam losses for a variety of ultra high charge state ions were measured as a function of cyclotron pressure and compared with the calculations from the existing models

  10. Vacuum improvements for ultra high charge state ion acceleration

    International Nuclear Information System (INIS)

    Xie, Z.Q.; Lyneis, C.M.; Clark, D.J.; Guy, A.; Lundgren, S.A.

    1999-01-01

    The installation of a second cryo panel has significantly improved the vacuum in the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory. The neutral pressure in the extraction region decreased from 1.2 x 10 -6 down to about 7 x 10 -7 Torr. The vacuum improvement reduces beam loss from charge changing collisions and enhances the cyclotron beam transmission, especially for the high charge state heavy ions. Tests with improved vacuum show the cyclotron transmission increased more than 50% (from 5.7% to 9.0%) for a Xe 27+ at 603 MeV, more than doubled for a Bi 41+ beam (from 1.9% % to 4.6%) at 904 MeV and tripled for a U 47+ beam (from 1.2% to 3.6%) at 1115 MeV. At about 5 MeV/nucleon 92 enA (2.2 pnA) for Bi 41+ and 14 enA (0.3 pnA) for U 47+ were extracted out of the 88-Inch Cyclotron Ion beams with charge states as high as U 64+ have been produced by the LBNL AECR-U ion source and accelerated through the cyclotron for the first time. The beam losses for a variety of ultra high charge state ions were measured as a function of cyclotron pressure and compared with the calculations from the existing models. (authors)

  11. Effect of Molecular Packing and Charge Delocalization on the Nonradiative Recombination of Charge-Transfer States in Organic Solar Cells

    KAUST Repository

    Chen, Xiankai

    2016-09-05

    In organic solar cells, a major source of energy loss is attributed to nonradiative recombination from the interfacial charge transfer states to the ground state. By taking pentacene–C60 complexes as model donor–acceptor systems, a comprehensive theoretical understanding of how molecular packing and charge delocalization impact these nonradiative recombination rates at donor–acceptor interfaces is provided.

  12. Battery Management Systems: Accurate State-of-Charge Indication for Battery-Powered Applications

    NARCIS (Netherlands)

    Pop, V.; Bergveld, H.J.; Danilov, D.; Regtien, Paulus P.L.; Notten, P.H.L.

    2008-01-01

    Battery Management Systems – Universal State-of-Charge indication for portable applications describes the field of State-of-Charge (SoC) indication for rechargeable batteries. With the emergence of battery-powered devices with an increasing number of power-hungry features, accurately estimating the

  13. Enhanced coulomb counting method for estimating state-of-charge and state-of-health of lithium-ion batteries

    International Nuclear Information System (INIS)

    Ng, Kong Soon; Moo, Chin-Sien; Chen, Yi-Ping; Hsieh, Yao-Ching

    2009-01-01

    The coulomb counting method is expedient for state-of-charge (SOC) estimation of lithium-ion batteries with high charging and discharging efficiencies. The charging and discharging characteristics are investigated and reveal that the coulomb counting method is convenient and accurate for estimating the SOC of lithium-ion batteries. A smart estimation method based on coulomb counting is proposed to improve the estimation accuracy. The corrections are made by considering the charging and operating efficiencies. Furthermore, the state-of-health (SOH) is evaluated by the maximum releasable capacity. Through the experiments that emulate practical operations, the SOC estimation method is verified to demonstrate the effectiveness and accuracy.

  14. Can independent coronal multiplanar reformatted images obtained using state-of-the-art MDCT scanners be used for primary interpretation of MDCT of the abdomen and pelvis? A feasibility study

    International Nuclear Information System (INIS)

    Sebastian, Sunit; Kalra, Mannudeep K.; Mittal, Pardeep; Saini, Sanjay; Small, William C.

    2007-01-01

    independent review of coronal reformats as compared with transverse images alone (p < 0.001). Readers' confidence was also found to be higher on coronal evaluations as compared to axial images (p < 0.01). There was good interobserver agreement between the two readers. Conclusion: Independent coronal multiplanar reformatted images obtained using state-of-the-art MDCT scanners show promise as the preferred orientation and can be useful for primary interpretation of MDCT of the abdomen and pelvis

  15. Space weather and coronal mass ejections

    CERN Document Server

    Howard, Tim

    2013-01-01

    Space weather has attracted a lot of attention in recent times. Severe space weather can disrupt spacecraft, and on Earth can be the cause of power outages and power station failure. It also presents a radiation hazard for airline passengers and astronauts. These ""magnetic storms"" are most commonly caused by coronal mass ejections, or CMES, which are large eruptions of plasma and magnetic field from the Sun that can reach speeds of several thousand km/s. In this SpringerBrief, Space Weather and Coronal Mass Ejections, author Timothy Howard briefly introduces the coronal mass ejection, its sc

  16. Charge loss experiments in surface channel CCD's explained by the McWhorter interface states model

    NARCIS (Netherlands)

    Penning De Vries, R.G.M.; Wallinga, Hans

    1985-01-01

    On the basis of the McWhorter interface states model the CCD charge loss is derived as a function of bias charge, signal charge and channel width. As opposed to existing models, the charge loss is now attributed to interface states in the entire gate area, even for high bias charge levels.

  17. CT-state dissociation and charge recombination in OPVs

    Energy Technology Data Exchange (ETDEWEB)

    Haeusermann, Roger; Reinke, Nils; Huber, Evelyne; Ruhstaller, Beat [ZHAW, Inst. of Computational Physics, Winterthur (Switzerland); Flatz, Thomas; Moos, Michael [Fluxim AG (Germany)

    2009-07-01

    The dissociation of the charge-transfer-state (CT) into free charge carriers is a very important process in the modeling of OPVs. A theoretical description of this mechanism has been developed by Onsager and Braun. The implications of this theory in real OPVs is not completely clear. Recently there was the proposition to reduce the whole device physics to the mechanisms at the donor-acceptor interface. This has been verified for a wide range of OPV materials, but it also raises questions about the universality of this simplification. In this study we developed a comprehensive device simulator. Our simulations have shown that a good agreement with measured J-V curves can be found by omitting any dissociation mechanism but at the same time increasing the influence of the Langevin recombination. This shows that distinct features of J-V curves are multi-causal and therefore a simplification by leaving out some of the mechanisms leads to an overestimation of the influence of other processes. We present the influence of the input parameters (CT-state dissociation, recombination and mobility) on the J-V curves and discuss in detail where and if each parameter can be seen separately in the shape of the J-V curve. The contributions of the different loss mechanisms, namely decay of excitons and CT-states as well as charge recombination will be addressed as function of material properties.

  18. Stark tuning and electrical charge state control of single divacancies in silicon carbide

    Science.gov (United States)

    de las Casas, Charles F.; Christle, David J.; Ul Hassan, Jawad; Ohshima, Takeshi; Son, Nguyen T.; Awschalom, David D.

    2017-12-01

    Neutrally charged divacancies in silicon carbide (SiC) are paramagnetic color centers whose long coherence times and near-telecom operating wavelengths make them promising for scalable quantum communication technologies compatible with existing fiber optic networks. However, local strain inhomogeneity can randomly perturb their optical transition frequencies, which degrades the indistinguishability of photons emitted from separate defects and hinders their coupling to optical cavities. Here, we show that electric fields can be used to tune the optical transition frequencies of single neutral divacancy defects in 4H-SiC over a range of several GHz via the DC Stark effect. The same technique can also control the charge state of the defect on microsecond timescales, which we use to stabilize unstable or non-neutral divacancies into their neutral charge state. Using fluorescence-based charge state detection, we show that both 975 nm and 1130 nm excitation can prepare their neutral charge state with near unity efficiency.

  19. Growth and decay of surface charges in grafts of Teflon in electrets states

    International Nuclear Information System (INIS)

    Spinelli, I.M.M.

    1971-01-01

    The greatest problem founded in a cardiovascular implant is the thrombus formation. Teflon grafts were used in electret state for prothesis in vena cava of dogs. To put these grafts in an electret state a corona discharge in air was used and homocharge was formed predominantly. To measure the formed surface charge the oscillating capacitor technique was used. In the electret state the grafts have showed an initial density of charge of 10- 8 C/cm 2 and the charge decay and time decay of the samples were measured under many conditions. We found two activation energies, E 2 =0.17 e V and E 3 =1.12 e V, due to rapid and slow decay, respectively. The charged grafts were sterilized with ethilene gas oxide and this process apparently did not influence the charges

  20. Positron study of negative charge states in order-disorder ferroelectrics

    Energy Technology Data Exchange (ETDEWEB)

    Troev, T.; Berovsky, K.; Peneva, S. [Bulgarian Academy of Sciences, Sofia (Bulgaria). Inst. for Nuclear Research and Nuclear Energy

    2001-07-01

    The positive positron charge opens the possibility for determining the changes in charge states in technologically important order-disorder ferroelectrics. Here we show that dipole polarization disordering within domains affects the positron annihilation mechanism. The positron lifetime parameters in triglycine sulphate (TGS) (NH{sub 3}CH{sub 2}COOH){sub 3}H{sub 2}SO{sub 4}, Rochelle salt (RS) NaKC{sub 4}H{sub 4}O{sub 6}.4H{sub 2}O and Potassium dihydrogen phosphate (KDP) KH{sub 2}PO{sub 4}, at different temperatures and gamma-irradiation doses depend on the charge point defects. The increase of the positron long lifetime component {tau}{sub 2} is proportional to the temperature and gamma-irradiation dose. In gamma irradiated TGS positrons are trapped in defect electron states of oxigen ions of two radicals CH{sub 2}COO{sup -} and NH{sub 3}CHCOO{sup -}. In RS positrons are trapped also in defect electron states of oxygen ions and OH groups. (orig.)

  1. State-of-charge indication in portable applications

    NARCIS (Netherlands)

    Pop, V.; Bergveld, H.J.; Notten, P.H.L.; Regtien, Paulus P.L.

    2005-01-01

    The known methods of state-of-charge (SoC) indication in portable applications are not accurate enough under all practical conditions. The method presented in this paper aims at designing and testing an SoC indication system capable of predicting the remaining capacity of the battery and the

  2. State-of-Charge Indication in Portable Applications

    NARCIS (Netherlands)

    Pop, V.; Bergveld, H.J.; Notten, P.H.L.; Regtien, Paulus P.L.

    2005-01-01

    The known methods of state-of-charge (SoC) indication in portable applications are not accurate enough under all practical conditions. The method presented in this paper aims at designing and testing an SoC indication system capable of predicting the remaining capacity of the battery and the

  3. State-of-charge indication for portable applications

    NARCIS (Netherlands)

    Pop, V.; Bergveld, H.J.; Notten, P.H.L.; Regtien, P.P.L.

    2005-01-01

    The known methods of state-of-charge (SoC) indication in portable applications are not accurate enough under all practical conditions. The method presented in this paper aims at designing and testing an SoC indication system capable of predicting the remaining capacity of the battery and the

  4. Techniques for enhancing the performance of high charge state ECR ion sources

    International Nuclear Information System (INIS)

    Xie, Z.Q.

    1999-01-01

    Electron Cyclotron Resonance ion source (ECRIS), which produces singly to highly charged ions, is widely used in heavy ion accelerators and is finding applications in industry. It has progressed significantly in recent years thanks to a few techniques, such as multiple-frequency plasma heating, higher mirror magnetic fields and a better cold electron donor. These techniques greatly enhance the production of highly charged ions. More than 1 emA of He 2+ and O 6+ , hundreds of eμA of O 7+ , Ne 8+ , Ar 12+ , more than 100 eμA of intermediate heavy ions with charge states up to Ne 9+ , Ar 13+ , Ca 13+ , Fe 13+ , Co 14+ and Kr 18+ , tens of eμA of heavy ions with charge states up to Xe 28+ , Au 35+ , Bi 34+ and U 34+ were produced at cw mode operation. At an intensity of about 1 eμA, the charge states for the heavy ions increased up to Xe 36+ , Au 46+ , Bi 47+ and U 48+ . More than an order of magnitude enhancement of fully stripped argon ions was achieved (I≥0.1 and h;eμA). Higher charge state ions up to Kr 35+ , Xe 46+ and U 64+ at low intensities were produced for the first time from an ECRIS. copyright 1999 American Institute of Physics

  5. Experimental evidence of state-selective charge transfer in inductively coupled plasma-atomic emission spectrometry

    International Nuclear Information System (INIS)

    Chan, George C.-Y.; Hieftje, Gary M.

    2004-01-01

    State-selective charge-transfer behavior was observed for Fe, Cr, Mn and Cu in inductively coupled plasma (ICP)-atomic emission spectrometry. Charge transfer from Ar + to Fe, Cr and Mn is state-selective because of inefficient collisional mixing of the quasiresonant charge-transfer energy levels with nearby levels. This low efficiency is the consequence of differences in electronic configuration of the core electrons. The reason for state-selective charge-transfer behavior to Cu is not clear, although a tentative explanation based on efficiency of intramultiplet and intermultiplet mixing for this special case is offered

  6. Evaluation of the Minifilament-Eruption Scenario for Solar Coronal Jets in Polar Coronal Holes

    Science.gov (United States)

    Baikie, Tomi K.; Sterling, Alphonse C.; Falconer, David; Moore, Ronald L.; Savage, Sabrina L.

    2016-01-01

    Solar coronal jets are suspected to result from magnetic reconnection low in the Sun's atmosphere. Sterling et al. (2015) looked as 20 jets in polar coronal holes, using X-ray images from the Hinode/X-Ray Telescope (XRT) and EUV images from the Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly (AIA). They suggested that each jet was driven by the eruption of twisted closed magnetic field carrying a small-scale filament, which they call a 'minifilament', and that the jet was produced by reconnection of the erupting field with surrounding open field. In this study, we carry out a more extensive examination of polar coronal jets. From 180 hours of XRT polar coronal hole observations spread over two years (2014-2016), we identified 130 clearly-identifiable X-ray jet events and thus determined an event rate of over 17 jets per day per in the Hinode/XRT field of view. From the broader set, we selected 25 of the largest and brightest events for further study in AIA 171, 193, 211, and 304 Angstrom images. We find that at least the majority of the jets follow the minifilament-eruption scenario, although for some cases the evolution of the minifilament in the onset of its eruption is more complex than presented in the simplified schematic of Sterling et al. (2015). For all cases in which we could make a clear determination, the spire of the X-ray jet drifted laterally away from the jet-base-edge bright point; this spire drift away from the bright point is consistent with expectations of the minifilament-eruption scenario for coronal-jet production. This work was supported with funding from the NASA/MSFC Hinode Project Office, and from the NASA HGI program.

  7. Charge transfer state in DBP:C70 organic solar cells

    DEFF Research Database (Denmark)

    Sherafatipour, Golenaz; Benduhn, Johannes; Spoltore, Donato

    -acceptor interface via delocalized charge-transfer (CT) states, which represents an intermediate state between the exciton dissociation and recombination back to the ground state. In this work we perform the electroluminescence (EL) created by bimolecular free career recombination and sensitive external quantum...

  8. Quantum State Transmission in a Superconducting Charge Qubit-Atom Hybrid

    Science.gov (United States)

    Yu, Deshui; Valado, María Martínez; Hufnagel, Christoph; Kwek, Leong Chuan; Amico, Luigi; Dumke, Rainer

    2016-01-01

    Hybrids consisting of macroscopic superconducting circuits and microscopic components, such as atoms and spins, have the potential of transmitting an arbitrary state between different quantum species, leading to the prospective of high-speed operation and long-time storage of quantum information. Here we propose a novel hybrid structure, where a neutral-atom qubit directly interfaces with a superconducting charge qubit, to implement the qubit-state transmission. The highly-excited Rydberg atom located inside the gate capacitor strongly affects the behavior of Cooper pairs in the box while the atom in the ground state hardly interferes with the superconducting device. In addition, the DC Stark shift of the atomic states significantly depends on the charge-qubit states. By means of the standard spectroscopic techniques and sweeping the gate voltage bias, we show how to transfer an arbitrary quantum state from the superconducting device to the atom and vice versa. PMID:27922087

  9. Future prospects for ECR ion sources with improved charge state distributions

    International Nuclear Information System (INIS)

    Alton, G.D.

    1995-01-01

    Despite the steady advance in the technology of the ECR ion source, present art forms have not yet reached their full potential in terms of charge state and intensity within a particular charge state, in part, because of the narrow band width. single-frequency microwave radiation used to heat the plasma electrons. This article identifies fundamentally important methods which may enhance the performances of ECR ion sources through the use of: (1) a tailored magnetic field configuration (spatial domain) in combination with single-frequency microwave radiation to create a large uniformly distributed ECR ''volume'' or (2) the use of broadband frequency domain techniques (variable-frequency, broad-band frequency, or multiple-discrete-frequency microwave radiation), derived from standard TWT technology, to transform the resonant plasma ''surfaces'' of traditional ECR ion sources into resonant plasma ''volume''. The creation of a large ECR plasma ''volume'' permits coupling of more power into the plasma, resulting in the heating of a much larger electron population to higher energies, thereby producing higher charge state ions and much higher intensities within a particular charge state than possible in present forms of' the source. The ECR ion source concepts described in this article offer exciting opportunities to significantly advance the-state-of-the-art of ECR technology and as a consequence, open new opportunities in fundamental and applied research and for a variety of industrial applications

  10. Comparison of Two Coronal Magnetic Field Models to Reconstruct a Sigmoidal Solar Active Region with Coronal Loops

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Aiying; Zhang, Huai [Key Laboratory of Computational Geodynamics, University of Chinese Academy of Sciences, Beijing 100049 (China); Jiang, Chaowei [Institute of Space Science and Applied Technology, Harbin Institute of Technology, Shenzhen, 518055 (China); Hu, Qiang; Gary, G. Allen; Wu, S. T. [Center for Space Plasma and Aeronomic Research, The University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Cao, Jinbin, E-mail: duanaiying@ucas.ac.cn, E-mail: hzhang@ucas.ac.cn, E-mail: chaowei@hit.edu.cn [School of Space and Environment, Beihang University, Beijing 100191 (China)

    2017-06-20

    Magnetic field extrapolation is an important tool to study the three-dimensional (3D) solar coronal magnetic field, which is difficult to directly measure. Various analytic models and numerical codes exist, but their results often drastically differ. Thus, a critical comparison of the modeled magnetic field lines with the observed coronal loops is strongly required to establish the credibility of the model. Here we compare two different non-potential extrapolation codes, a nonlinear force-free field code (CESE–MHD–NLFFF) and a non-force-free field (NFFF) code, in modeling a solar active region (AR) that has a sigmoidal configuration just before a major flare erupted from the region. A 2D coronal-loop tracing and fitting method is employed to study the 3D misalignment angles between the extrapolated magnetic field lines and the EUV loops as imaged by SDO /AIA. It is found that the CESE–MHD–NLFFF code with preprocessed magnetogram performs the best, outputting a field that matches the coronal loops in the AR core imaged in AIA 94 Å with a misalignment angle of ∼10°. This suggests that the CESE–MHD–NLFFF code, even without using the information of the coronal loops in constraining the magnetic field, performs as good as some coronal-loop forward-fitting models. For the loops as imaged by AIA 171 Å in the outskirts of the AR, all the codes including the potential field give comparable results of the mean misalignment angle (∼30°). Thus, further improvement of the codes is needed for a better reconstruction of the long loops enveloping the core region.

  11. Observational Analysis of Coronal Fans

    Science.gov (United States)

    Talpeanu, D.-C.; Rachmeler, L; Mierla, Marilena

    2017-01-01

    Coronal fans (see Figure 1) are bright observational structures that extend to large distances above the solar surface and can easily be seen in EUV (174 angstrom) above the limb. They have a very long lifetime and can live up to several Carrington rotations (CR), remaining relatively stationary for many months. Note that they are not off-limb manifestation of similarly-named active region fans. The solar conditions required to create coronal fans are not well understood. The goal of this research was to find as many associations as possible of coronal fans with other solar features and to gain a better understanding of these structures. Therefore, we analyzed many fans and created an overview of their properties. We present the results of this statistical analysis and also a case study on the longest living fan.

  12. Charge state distribution of ionic kryptons after photoionization

    International Nuclear Information System (INIS)

    Cai Xiaohong

    1992-01-01

    Monochromatic X-rays from the 2.3 GeV synchrotron at University Bonn (Germany) are employed for inner shell excitation of krypton. Various ionic kryptons and a number of electrons are produced due to photoionization. In order to study the equilibrium charge state distribution of ionic kryptons, a time of flight mass spectrometer is set up and used to measure the resulting ionic charge spectra with photo energies near the L 1 - , L 2 - and L 3 - absorption edges of krypton. The energy dependence of relative probabilities is presented

  13. The acceleration of electrons at a spherical coronal shock in a streamer-like coronal field

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Xiangliang, E-mail: kongx@sdu.edu.cn; Chen, Yao, E-mail: yaochen@sdu.edu.cn [Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, and Institute of Space Sciences, Shandong University, Weihai, Shandong 264209 (China); Guo, Fan, E-mail: guofan.ustc@gmail.com [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2016-03-25

    We study the effect of large-scale coronal magnetic field on the electron acceleration at a spherical coronal shock using a test-particle method. The coronal field is approximated by an analytical solution with a streamer-like magnetic field featured by partially open magnetic field and a current sheet at the equator atop the closed region. It shows that the closed field plays the role of a trapping agency of shock-accelerated electrons, allowing for repetitive reflection and acceleration, therefore can greatly enhance the shock-electron acceleration efficiency. It is found that, with an ad hoc pitch-angle scattering, electron injected in the open field at the shock flank can be accelerated to high energies as well. In addition, if the shock is faster or stronger, a relatively harder electron energy spectrum and a larger maximum energy can be achieved.

  14. Optimizing Global Coronal Magnetic Field Models Using Image-Based Constraints

    Science.gov (United States)

    Jones-Mecholsky, Shaela I.; Davila, Joseph M.; Uritskiy, Vadim

    2016-01-01

    The coronal magnetic field directly or indirectly affects a majority of the phenomena studied in the heliosphere. It provides energy for coronal heating, controls the release of coronal mass ejections, and drives heliospheric and magnetospheric activity, yet the coronal magnetic field itself has proven difficult to measure. This difficulty has prompted a decades-long effort to develop accurate, timely, models of the field, an effort that continues today. We have developed a method for improving global coronal magnetic field models by incorporating the type of morphological constraints that could be derived from coronal images. Here we report promising initial tests of this approach on two theoretical problems, and discuss opportunities for application.

  15. Charge transport through image charged stabilized states in a single molecule single electron transistor device

    International Nuclear Information System (INIS)

    Hedegard, Per; Bjornholm, Thomas

    2005-01-01

    The present paper gives an elaborate theoretical description of a new molecular charge transport mechanism applying to a single molecule trapped between two macroscopic electrodes in a solid state device. It is shown by a Hubbard type model of the electronic and electrostatic interactions, that the close proximity of metal electrodes may allow electrons to tunnel from the electrode directly into very localized image charge stabilized states on the molecule. Due to this mechanism, an exceptionally large number of redox states may be visited within an energy scale which would normally not allow the molecular HOMO-LUMO gap to be transversed. With a reasonable set of parameters, a good fit to recent experimental values may be obtained. The theoretical model is furthermore used to search for the physical boundaries of this effect, and it is found that a rather narrow geometrical space is available for the new mechanism to work: in the specific case of oligophenylenevinylene molecules recently explored in such devices several atoms in the terminal benzene rings need to be at van der Waal's distance to the electrode in order for the mechanism to work. The model predicts, that chemisorption of the terminal benzene rings too gold electrodes will impede the image charge effect very significantly because the molecule is pushed away from the electrode by the covalent thiol-gold bond

  16. The physical structure of coronal holes

    International Nuclear Information System (INIS)

    Pneuman, G.W.

    1978-11-01

    The longitudinal geometrical structure of solar wind streams as observed at the orbit of earth is governed by two mechanisms - solar rotation and, most importantly, the geometry of the inner coronal magnetic fields. Here, we study the influence of the latter for the polar coronal hole observed by Skylab in 1973 and modeled by Munro and Jackson (1977). The influence of coronal heating on the properties of the solar wind in this geometry is also investigated. To do this, a crude exponentially damped heating function similar to that used by Kopp and Orrall (1976) is introduced into the solar wind equations. We find that increased heating produces higher temperatures in the inner corona but has little effect upon the temperature at 1 A.U. However, the density at 1 A.U. is increased significantly due to the increase in scale height. The most surprising consequence of coronal heating is its effect on the solar wind velocity, being that the velocity at 1 A.U. is actually decreased by heating in the inner corona. Physical reasons for this effect are discussed. (orig./WL) [de

  17. Solar wind acceleration in coronal holes

    International Nuclear Information System (INIS)

    Kopp, R.A.

    1978-01-01

    Past attempts to explain the large solar wind velocities in high speed streams by theoretical models of the expansion have invoked either extended nonthermal heating of the corona, heat flux inhibition, or direct addition of momentum to the expanding coronal plasma. Several workers have shown that inhibiting the heat flux at low coronal densities is probably not adequate to explain quantitatively the observed plasma velocities in high speed streams. It stressed that, in order to account for both these large plasma velocities and the low densities found in coronal holes (from which most high speed streams are believed to emanate), extended heating by itself will not suffice. One needs a nonthermal mechanism to provide the bulk acceleration of the high wind plasma close to the sun, and the most likely candidate at present is direct addition of the momentum carried by outward-propagating waves to the expanding corona. Some form of momentum addition appears to be absolutely necessary if one hopes to build quantitatively self-consistent models of coronal holes and high speed solar wind streams

  18. Space- and Ground-based Coronal Spectro-Polarimetry

    Science.gov (United States)

    Fineschi, Silvano; Bemporad, Alessandro; Rybak, Jan; Capobianco, Gerardo

    This presentation gives an overview of the near-future perspectives of ultraviolet and visible-light spectro-polarimetric instrumentation for probing coronal magnetism from space-based and ground-based observatories. Spectro-polarimetric imaging of coronal emission-lines in the visible-light wavelength-band provides an important diagnostics tool of the coronal magnetism. The interpretation in terms of Hanle and Zeeman effect of the line-polarization in forbidden emission-lines yields information on the direction and strength of the coronal magnetic field. As study case, this presentation will describe the Torino Coronal Magnetograph (CorMag) for the spectro-polarimetric observation of the FeXIV, 530.3 nm, forbidden emission-line. CorMag - consisting of a Liquid Crystal (LC) Lyot filter and a LC linear polarimeter - has been recently installed on the Lomnicky Peak Observatory 20cm Zeiss coronagraph. The preliminary results from CorMag will be presented. The linear polarization by resonance scattering of coronal permitted line-emission in the ultraviolet (UV)can be modified by magnetic fields through the Hanle effect. Space-based UV spectro-polarimeters would provide an additional tool for the disgnostics of coronal magnetism. As a case study of space-borne UV spectro-polarimeters, this presentation will describe the future upgrade of the Sounding-rocket Coronagraphic Experiment (SCORE) to include the capability of imaging polarimetry of the HI Lyman-alpha, 121.6 nm. SCORE is a multi-wavelength imager for the emission-lines, HeII 30.4 nm and HI 121.6 nm, and visible-light broad-band emission of the polarized K-corona. SCORE has flown successfully in 2009. This presentation will describe how in future re-flights SCORE could observe the expected Hanle effect in corona with a HI Lyman-alpha polarimeter.

  19. Coronal rain in magnetic bipolar weak fields

    Science.gov (United States)

    Xia, C.; Keppens, R.; Fang, X.

    2017-07-01

    Aims: We intend to investigate the underlying physics for the coronal rain phenomenon in a representative bipolar magnetic field, including the formation and the dynamics of coronal rain blobs. Methods: With the MPI-AMRVAC code, we performed three dimensional radiative magnetohydrodynamic (MHD) simulation with strong heating localized on footpoints of magnetic loops after a relaxation to quiet solar atmosphere. Results: Progressive cooling and in-situ condensation starts at the loop top due to radiative thermal instability. The first large-scale condensation on the loop top suffers Rayleigh-Taylor instability and becomes fragmented into smaller blobs. The blobs fall vertically dragging magnetic loops until they reach low-β regions and start to fall along the loops from loop top to loop footpoints. A statistic study of the coronal rain blobs finds that small blobs with masses of less than 1010 g dominate the population. When blobs fall to lower regions along the magnetic loops, they are stretched and develop a non-uniform velocity pattern with an anti-parallel shearing pattern seen to develop along the central axis of the blobs. Synthetic images of simulated coronal rain with Solar Dynamics Observatory Atmospheric Imaging Assembly well resemble real observations presenting dark falling clumps in hot channels and bright rain blobs in a cool channel. We also find density inhomogeneities during a coronal rain "shower", which reflects the observed multi-stranded nature of coronal rain. Movies associated to Figs. 3 and 7 are available at http://www.aanda.org

  20. THE CORONAL ABUNDANCES OF MID-F DWARFS

    International Nuclear Information System (INIS)

    Wood, Brian E.; Laming, J. Martin

    2013-01-01

    A Chandra spectrum of the moderately active nearby F6 V star π 3 Ori is used to study the coronal properties of mid-F dwarfs. We find that π 3 Ori's coronal emission measure distribution is very similar to those of moderately active G and K dwarfs, with an emission measure peak near log T = 6.6 seeming to be ubiquitous for such stars. In contrast to coronal temperature, coronal abundances are known to depend on spectral type for main sequence stars. Based on this previously known relation, we expected π 3 Ori's corona to exhibit an extremely strong ''first ionization potential (FIP) effect'', a phenomenon first identified on the Sun where elements with low FIP are enhanced in the corona. We instead find that π 3 Ori's corona exhibits a FIP effect essentially identical to that of the Sun and other early G dwarfs, perhaps indicating that the increase in FIP bias toward earlier spectral types stops or at least slows for F stars. We find that π 3 Ori's coronal characteristics are significantly different from two previously studied mid-F stars, Procyon (F5 IV-V) and τ Boo (F7 V). We believe π 3 Ori is more representative of the coronal characteristics of mid-F dwarfs, with Procyon being different because of luminosity class, and τ Boo being different because of the effects of one of two close companions, one stellar (τ Boo B: M2 V) and one planetary.

  1. Classical/quantum correspondence in state selective charge transfer and excitation reactions involving highly charged ions and hydrogen

    International Nuclear Information System (INIS)

    Purkait, M

    2009-01-01

    State selective charge transfer and excitation cross sections for collisions of Ne q+ (q = 1-10) with atomic hydrogen are calculated within the framework of Classical Trajectory Monte Carlo (CTMC) method and Boundary Corrected Continuum Intermediate State (BCCIS) approximation.

  2. New Evidence that Magnetoconvection Drives Solar–Stellar Coronal Heating

    Energy Technology Data Exchange (ETDEWEB)

    Tiwari, Sanjiv K.; Panesar, Navdeep K.; Moore, Ronald L.; Winebarger, Amy R. [NASA Marshall Space Flight Center, Mail Code ST 13, Huntsville, AL 35812 (United States); Thalmann, Julia K., E-mail: sanjivtiwari80@gmail.com [Institute of Physics/IGAM, University of Graz, Universittsplatz 5/II, A-8010 Graz (Austria)

    2017-07-10

    How magnetic energy is injected and released in the solar corona, keeping it heated to several million degrees, remains elusive. Coronal heating generally increases with increasing magnetic field strength. From a comparison of a nonlinear force-free model of the three-dimensional active region coronal field to observed extreme-ultraviolet loops, we find that (1) umbra-to-umbra coronal loops, despite being rooted in the strongest magnetic flux, are invisible, and (2) the brightest loops have one foot in an umbra or penumbra and the other foot in another sunspot’s penumbra or in unipolar or mixed-polarity plage. The invisibility of umbra-to-umbra loops is new evidence that magnetoconvection drives solar-stellar coronal heating: evidently, the strong umbral field at both ends quenches the magnetoconvection and hence the heating. Broadly, our results indicate that depending on the field strength in both feet, the photospheric feet of a coronal loop on any convective star can either engender or quench coronal heating in the loop’s body.

  3. Coronal Mass Ejections An Introduction

    CERN Document Server

    Howard, Timothy

    2011-01-01

    In times of growing technological sophistication and of our dependence on electronic technology, we are all affected by space weather. In its most extreme form, space weather can disrupt communications, damage and destroy spacecraft and power stations, and increase radiation exposure to astronauts and airline passengers. Major space weather events, called geomagnetic storms, are large disruptions in the Earth’s magnetic field brought about by the arrival of enormous magnetized plasma clouds from the Sun. Coronal mass ejections (CMEs) contain billions of tons of plasma and hurtle through space at speeds of several million miles per hour. Understanding coronal mass ejections and their impact on the Earth is of great interest to both the scientific and technological communities. This book provides an introduction to coronal mass ejections, including a history of their observation and scientific revelations, instruments and theory behind their detection and measurement, and the status quo of theories describing...

  4. High ion charge states in a high-current, short-pulse, vacuum ARC ion sources

    International Nuclear Information System (INIS)

    Anders, A.; Brown, I.; MacGill, R.; Dickinson, M.

    1996-01-01

    Ions of the cathode material are formed at vacuum arc cathode spots and extracted by a grid system. The ion charge states (typically 1-4) depend on the cathode material and only little on the discharge current as long as the current is low. Here the authors report on experiments with short pulses (several μs) and high currents (several kA); this regime of operation is thus approaching a more vacuum spark-like regime. Mean ion charge states of up to 6.2 for tungsten and 3.7 for titanium have been measured, with the corresponding maximum charge states of up to 8+ and 6+, respectively. The results are discussed in terms of Saha calculations and freezing of the charge state distribution

  5. High ion charge states in a high-current, short-pulse, vacuum arc ion source

    International Nuclear Information System (INIS)

    Anders, A.; Brown, I.; MacGill, R.; Dickinson, M.

    1995-09-01

    Ions of the cathode material are formed at vacuum arc cathode spots and extracted by a grid system. The ion charge states (typically 1--4) depend on the cathode material and only little on the discharge current as long as the current is low. Here the authors report on experiments with short pulses (several micros) and high currents (several kA); this regime of operation is thus approaching a more vacuum spark-like regime. Mean ion charge states of up to 6.2 for tungsten and 3.7 for titanium have been measured, with the corresponding maximum charge states of up to 8+ and 6+, respectively. The results are discussed in terms of Saha calculations and freezing of the charge state distribution

  6. Universal state-of-charge indication for portable applications

    NARCIS (Netherlands)

    Pop, V.

    2007-01-01

    Many leading semiconductors companies (e.g. Philips, Texas Instruments, Microchip, Maxim, etc.) are paying even more attention to accurate State-of-Charge (SoC) indication. Following the technological revolution and the appearance of more power consuming devices on the automotive electronics and

  7. Free Magnetic Energy and Coronal Heating

    Science.gov (United States)

    Winebarger, Amy; Moore, Ron; Falconer, David

    2012-01-01

    Previous work has shown that the coronal X-ray luminosity of an active region increases roughly in direct proportion to the total photospheric flux of the active region's magnetic field (Fisher et al. 1998). It is also observed, however, that the coronal luminosity of active regions of nearly the same flux content can differ by an order of magnitude. In this presentation, we analyze 10 active regions with roughly the same total magnetic flux. We first determine several coronal properties, such as X-ray luminosity (calculated using Hinode XRT), peak temperature (calculated using Hinode EIS), and total Fe XVIII emission (calculated using SDO AIA). We present the dependence of these properties on a proxy of the free magnetic energy of the active region

  8. Measurements of EUV coronal holes and open magnetic flux

    International Nuclear Information System (INIS)

    Lowder, C.; Qiu, J.; Leamon, R.; Liu, Y.

    2014-01-01

    Coronal holes are regions on the Sun's surface that map the footprints of open magnetic field lines. We have developed an automated routine to detect and track boundaries of long-lived coronal holes using full-disk extreme-ultraviolet (EUV) images obtained by SOHO/EIT, SDO/AIA, and STEREO/EUVI. We measure coronal hole areas and magnetic flux in these holes, and compare the measurements with calculations by the potential field source surface (PFSS) model. It is shown that, from 1996 through 2010, the total area of coronal holes measured with EIT images varies between 5% and 17% of the total solar surface area, and the total unsigned open flux varies between (2-5)× 10 22 Mx. The solar cycle dependence of these measurements is similar to the PFSS results, but the model yields larger hole areas and greater open flux than observed by EIT. The AIA/EUVI measurements from 2010-2013 show coronal hole area coverage of 5%-10% of the total surface area, with significant contribution from low latitudes, which is under-represented by EIT. AIA/EUVI have measured much enhanced open magnetic flux in the range of (2-4)× 10 22 Mx, which is about twice the flux measured by EIT, and matches with the PFSS calculated open flux, with discrepancies in the location and strength of coronal holes. A detailed comparison between the three measurements (by EIT, AIA-EUVI, and PFSS) indicates that coronal holes in low latitudes contribute significantly to the total open magnetic flux. These low-latitude coronal holes are not well measured with either the He I 10830 line in previous studies, or EIT EUV images; neither are they well captured by the static PFSS model. The enhanced observations from AIA/EUVI allow a more accurate measure of these low-latitude coronal holes and their contribution to open magnetic flux.

  9. Coronal and interplanetary propagation, interplanetary acceleration, cosmic-ray observations by deep space network and anomalous component

    International Nuclear Information System (INIS)

    Ng, C.K.

    1986-01-01

    The purpose is to provide an overview of the contributions presented in sessions SH3, SH1.5, SH4.6 and SH4.7 of the 19th International Cosmic Ray Conference. These contributed papers indicate that steady progress continues to be made in both the observational and the theoretical aspects of the transport and acceleration of energetic charged particles in the heliosphere. Studies of solar and interplanetary particles have placed emphasis on particle directional distributions in relation to pitch-angle scattering and magnetic focusing, on the rigidity and spatial dependence of the mean free path, and on new propagation regimes in the inner and outer heliosphere. Coronal propagation appears in need of correlative multi-spacecraft studies in association with detailed observation of the flare process and coronal magnetic structures. Interplanetary acceleration has now gone into a consolidation phase, with theories being worked out in detail and checked against observation

  10. Coronal and interplanetary propagation, interplanetary acceleration, cosmic-ray observations by deep space network and anomalous component

    Science.gov (United States)

    Ng, C. K.

    1986-01-01

    The purpose is to provide an overview of the contributions presented in sessions SH3, SH1.5, SH4.6 and SH4.7 of the 19th International Cosmic Ray Conference. These contributed papers indicate that steady progress continues to be made in both the observational and the theoretical aspects of the transport and acceleration of energetic charged particles in the heliosphere. Studies of solar and interplanetary particles have placed emphasis on particle directional distributions in relation to pitch-angle scattering and magnetic focusing, on the rigidity and spatial dependence of the mean free path, and on new propagation regimes in the inner and outer heliosphere. Coronal propagation appears in need of correlative multi-spacecraft studies in association with detailed observation of the flare process and coronal magnetic structures. Interplanetary acceleration has now gone into a consolidation phase, with theories being worked out in detail and checked against observation.

  11. Charge independence and charge symmetry breaking interactions and the Coulomb energy anomaly in isobaric analog states

    International Nuclear Information System (INIS)

    Suzuki, Toshio; Sagawa, H.; Giai, N. van.

    1992-01-01

    Effects of CIB (charge independence breaking) and CSB (charge symmetry breaking) interactions on the Coulomb displacement energies of isobaric analog states are investigated for 48 Ca, 90 Zr and 208 Pb. Mass number dependence of the Coulomb energy anomalies is well explained when CIB and CSB interactions are used which reproduce the differences of the scattering lengths as well as those of the effective ranges of low energy nucleon-nucleon scattering. (author) 17 refs., 3 figs., 3 tabs

  12. Performance on the low charge state laser ion source in BNL

    Energy Technology Data Exchange (ETDEWEB)

    Okamura, M.; Alessi, J.; Beebe, E.; Costanzo, M.; DeSanto, L.; Jamilkowski, J.; Kanesue, T.; Lambiase, R.; Lehn, D.; Liaw, C. J.; McCafferty, D.; Morris, J.; Olsen, R.; Pikin, A.; Raparia, D.; Steszyn, A.; Ikeda, S.

    2015-09-07

    On March 2014, a Laser Ion Source (LIS) was commissioned which delivers high-brightness, low-charge-state heavy ions for the hadron accelerator complex in Brookhaven National Laboratory (BNL). Since then, the LIS has provided many heavy ion species successfully. The low-charge-state (mostly singly charged) beams are injected to the Electron Beam Ion Source (EBIS), where ions are then highly ionized to fit to the following accelerator’s Q/M acceptance, like Au32+. Recently we upgraded the LIS to be able to provide two different beams into EBIS on a pulse-to-pulse basis. Now the LIS is simultaneously providing beams for both the Relativistic Heavy Ion Collider (RHIC) and NASA Space Radiation Laboratory (NSRL).

  13. The study towards high intensity high charge state laser ion sources.

    Science.gov (United States)

    Zhao, H Y; Jin, Q Y; Sha, S; Zhang, J J; Li, Z M; Liu, W; Sun, L T; Zhang, X Z; Zhao, H W

    2014-02-01

    As one of the candidate ion sources for a planned project, the High Intensity heavy-ion Accelerator Facility, a laser ion source has been being intensively studied at the Institute of Modern Physics in the past two years. The charge state distributions of ions produced by irradiating a pulsed 3 J/8 ns Nd:YAG laser on solid targets of a wide range of elements (C, Al, Ti, Ni, Ag, Ta, and Pb) were measured with an electrostatic ion analyzer spectrometer, which indicates that highly charged ions could be generated from low-to-medium mass elements with the present laser system, while the charge state distributions for high mass elements were relatively low. The shot-to-shot stability of ion pulses was monitored with a Faraday cup for carbon target. The fluctuations within ±2.5% for the peak current and total charge and ±6% for pulse duration were demonstrated with the present setup of the laser ion source, the suppression of which is still possible.

  14. Charge state of finely divided conducting systems in dielectric matrix

    International Nuclear Information System (INIS)

    Medvedev, Yu.V.; Grishin, A.M.

    2001-01-01

    The calculation of the high statistic sum Z of the charged metal granules in the dielectric matrix is carried out with an account of the excess number of the Fermi-particles fluctuations on the granules. Application of a microscopic Hamiltonian for the energy of electrostatic interaction between the charge densities in the system makes it possible to accomplish these calculations in the average field approximation. The effect of the number of the Fermi-particles fluctuations on the charge state of the finely divided granules in the dielectric matrix is studied. It is supposed that the charge exchange between the composite metal elements occurs on the account of the electron overbarrier heat transfer. It is followed from the system high statistic sum calculation results that the i-granule medium charge is connected by the nonlinear ratio with the conductors V i potentials [ru

  15. DARK JETS IN SOLAR CORONAL HOLES

    Energy Technology Data Exchange (ETDEWEB)

    Young, Peter R. [College of Science, George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States)

    2015-03-10

    A new solar feature termed a dark jet is identified from observations of an extended solar coronal hole that was continuously monitored for over 44 hr by the Extreme Ultraviolet Imaging Spectrometer on board the Hinode spacecraft in 2011 February 8–10 as part of Hinode Operation Plan No. 177 (HOP 177). Line of sight (LOS) velocity maps derived from the coronal Fe xii λ195.12 emission line, formed at 1.5 MK, revealed a number of large-scale, jet-like structures that showed significant blueshifts. The structures had either weak or no intensity signal in 193 Å filter images from the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory, suggesting that the jets are essentially invisible to imaging instruments. The dark jets are rooted in bright points and occur both within the coronal hole and at the quiet Sun–coronal hole boundary. They exhibit a wide range of shapes, from narrow columns to fan-shaped structures, and sometimes multiple jets are seen close together. A detailed study of one dark jet showed LOS speeds increasing along the jet axis from 52 to 107 km s{sup −1} and a temperature of 1.2–1.3 MK. The low intensity of the jet was due either to a small filling factor of 2% or to a curtain-like morphology. From the HOP 177 sample, dark jets are as common as regular coronal hole jets, but their low intensity suggests a mass flux around two orders of magnitude lower.

  16. Solar Wind Associated with Near Equatorial Coronal Hole M ...

    Indian Academy of Sciences (India)

    2015-05-25

    May 25, 2015 ... coronal hole and solar wind. For both the wavelength bands, we also com- pute coronal hole radiative energy near the earth and it is found to be of similar order as that of solar wind energy. However, for the wavelength. 193 Å, owing to almost similar magnitudes of energy emitted by coronal hole and ...

  17. THE CONTRIBUTION OF CORONAL JETS TO THE SOLAR WIND

    Energy Technology Data Exchange (ETDEWEB)

    Lionello, R.; Török, T.; Titov, V. S.; Mikić, Z.; Linker, J. A. [Predictive Science Inc., 9990 Mesa Rim Road, Suite 170, San Diego, CA 92121 (United States); Leake, J. E.; Linton, M. G., E-mail: lionel@predsci.com [US Naval Research Laboratory 4555 Overlook Avenue, SW Washington, DC 20375 (United States)

    2016-11-01

    Transient collimated plasma eruptions in the solar corona, commonly known as coronal (or X-ray) jets, are among the most interesting manifestations of solar activity. It has been suggested that these events contribute to the mass and energy content of the corona and solar wind, but the extent of these contributions remains uncertain. We have recently modeled the formation and evolution of coronal jets using a three-dimensional (3D) magnetohydrodynamic (MHD) code with thermodynamics in a large spherical domain that includes the solar wind. Our model is coupled to 3D MHD flux-emergence simulations, i.e., we use boundary conditions provided by such simulations to drive a time-dependent coronal evolution. The model includes parametric coronal heating, radiative losses, and thermal conduction, which enables us to simulate the dynamics and plasma properties of coronal jets in a more realistic manner than done so far. Here, we employ these simulations to calculate the amount of mass and energy transported by coronal jets into the outer corona and inner heliosphere. Based on observed jet-occurrence rates, we then estimate the total contribution of coronal jets to the mass and energy content of the solar wind to (0.4–3.0)% and (0.3–1.0)%, respectively. Our results are largely consistent with the few previous rough estimates obtained from observations, supporting the conjecture that coronal jets provide only a small amount of mass and energy to the solar wind. We emphasize, however, that more advanced observations and simulations (including parametric studies) are needed to substantiate this conjecture.

  18. Coronal Magnetism and Forward Solarsoft Idl Package

    Science.gov (United States)

    Gibson, S. E.

    2014-12-01

    The FORWARD suite of Solar Soft IDL codes is a community resource for model-data comparison, with a particular emphasis on analyzing coronal magnetic fields. FORWARD may be used both to synthesize a broad range of coronal observables, and to access and compare to existing data. FORWARD works with numerical model datacubes, interfaces with the web-served Predictive Science Inc MAS simulation datacubes and the Solar Soft IDL Potential Field Source Surface (PFSS) package, and also includes several analytic models (more can be added). It connects to the Virtual Solar Observatory and other web-served observations to download data in a format directly comparable to model predictions. It utilizes the CHIANTI database in modeling UV/EUV lines, and links to the CLE polarimetry synthesis code for forbidden coronal lines. FORWARD enables "forward-fitting" of specific observations, and helps to build intuition into how the physical properties of coronal magnetic structures translate to observable properties.

  19. Origin of interface states and oxide charges generated by ionizing radiation

    International Nuclear Information System (INIS)

    Sah, C.T.

    1976-01-01

    The randomly located trivalent silicon atoms are shown to account for the thermally generated interface states at the SiO 2 -Si interface. The interface state density is greatly reduced in water containing ambients at low temperatures (450 0 C) by forming trivalent silicon hydroxide bonds. Interface states are regenerated when the /triple bond/Si-OH bonds are broken by ionizing radiation and the OH ions are drifted away. In the bulk of the oxide film, the trivalent silicon and the interstitial oxygen donor centers are shown to be responsible for the heat and radiation generated positive space charge build-up (oxide charge) in thermally grown silicon oxide

  20. The influence of the beam charge state on the analytical calculation of RBS and ERDA spectra

    Energy Technology Data Exchange (ETDEWEB)

    Barradas, Nuno P., E-mail: nunoni@ctn.ist.utl.pt [Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, E.N. 10 ao km 139,7, 2695-066 Bobadela LRS (Portugal); Kosmata, Marcel [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328 Dresden (Germany); Globalfoundries, Wilschdorfer Landstraße 101, 01109 Dresden (Germany); Hanf, Daniel; Munnik, Frans [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328 Dresden (Germany)

    2016-03-15

    Analytical codes dedicated to the analysis of Ion Beam Analysis data rely on the accuracy of both the calculations and of basic data such as scattering cross sections and stopping powers. So far, the effect of the beam charge state of the incoming beam has been disregard by general purpose analytical codes such as NDF. In fact, the codes implicitly assume that the beam always has the equilibrium charge state distribution, by using tabulated stopping power values e.g. from SRIM, which are in principle valid for the effective charge state. The dependence of the stopping power with the changing charge state distribution is ignored. This assumption is reasonable in most cases, but for high resolution studies the actual change of the charge state distribution from the initial beam charge state towards equilibrium as it enters and traverses the sample must be taken into account, as it influences the shape of the observed data. In this work, we present an analytical calculation, implemented in NDF, that takes this effect into account. For elastic recoil detection analysis (ERDA), the changing charge state distribution of the recoils can also be taken into account. We apply the calculation to the analysis of experimental high depth resolution ERDA data for various oxide layers collected using a magnetic spectrometer.

  1. Adaptive unscented Kalman filtering for state of charge estimation of a lithium-ion battery for electric vehicles

    International Nuclear Information System (INIS)

    Sun, Fengchun; Hu, Xiaosong; Zou, Yuan; Li, Siguang

    2011-01-01

    An accurate battery State of Charge estimation is of great significance for battery electric vehicles and hybrid electric vehicles. This paper presents an adaptive unscented Kalman filtering method to estimate State of Charge of a lithium-ion battery for battery electric vehicles. The adaptive adjustment of the noise covariances in the State of Charge estimation process is implemented by an idea of covariance matching in the unscented Kalman filter context. Experimental results indicate that the adaptive unscented Kalman filter-based algorithm has a good performance in estimating the battery State of Charge. A comparison with the adaptive extended Kalman filter, extended Kalman filter, and unscented Kalman filter-based algorithms shows that the proposed State of Charge estimation method has a better accuracy. -- Highlights: → Adaptive unscented Kalman filtering is proposed to estimate State of Charge of a lithium-ion battery for electric vehicles. → The proposed method has a good performance in estimating the battery State of Charge. → A comparison with three other Kalman filtering algorithms shows that the proposed method has a better accuracy.

  2. Multiconfiguration Pair-Density Functional Theory Outperforms Kohn-Sham Density Functional Theory and Multireference Perturbation Theory for Ground-State and Excited-State Charge Transfer.

    Science.gov (United States)

    Ghosh, Soumen; Sonnenberger, Andrew L; Hoyer, Chad E; Truhlar, Donald G; Gagliardi, Laura

    2015-08-11

    The correct description of charge transfer in ground and excited states is very important for molecular interactions, photochemistry, electrochemistry, and charge transport, but it is very challenging for Kohn-Sham (KS) density functional theory (DFT). KS-DFT exchange-correlation functionals without nonlocal exchange fail to describe both ground- and excited-state charge transfer properly. We have recently proposed a theory called multiconfiguration pair-density functional theory (MC-PDFT), which is based on a combination of multiconfiguration wave function theory with a new type of density functional called an on-top density functional. Here we have used MC-PDFT to study challenging ground- and excited-state charge-transfer processes by using on-top density functionals obtained by translating KS exchange-correlation functionals. For ground-state charge transfer, MC-PDFT performs better than either the PBE exchange-correlation functional or CASPT2 wave function theory. For excited-state charge transfer, MC-PDFT (unlike KS-DFT) shows qualitatively correct behavior at long-range with great improvement in predicted excitation energies.

  3. Dynamics of Coronal Hole Boundaries

    Energy Technology Data Exchange (ETDEWEB)

    Higginson, A. K.; Zurbuchen, T. H. [Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Antiochos, S. K.; DeVore, C. R. [Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Wyper, P. F. [Universities Space Research Association, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States)

    2017-03-10

    Remote and in situ observations strongly imply that the slow solar wind consists of plasma from the hot, closed-field corona that is released onto open magnetic field lines. The Separatrix Web theory for the slow wind proposes that photospheric motions at the scale of supergranules are responsible for generating dynamics at coronal-hole boundaries, which result in the closed plasma release. We use three-dimensional magnetohydrodynamic simulations to determine the effect of photospheric flows on the open and closed magnetic flux of a model corona with a dipole magnetic field and an isothermal solar wind. A rotational surface motion is used to approximate photospheric supergranular driving and is applied at the boundary between the coronal hole and helmet streamer. The resulting dynamics consist primarily of prolific and efficient interchange reconnection between open and closed flux. The magnetic flux near the coronal-hole boundary experiences multiple interchange events, with some flux interchanging over 50 times in one day. Additionally, we find that the interchange reconnection occurs all along the coronal-hole boundary and even produces a lasting change in magnetic-field connectivity in regions that were not driven by the applied motions. Our results show that these dynamics should be ubiquitous in the Sun and heliosphere. We discuss the implications of our simulations for understanding the observed properties of the slow solar wind, with particular focus on the global-scale consequences of interchange reconnection.

  4. Features of solar wind streams on June 21-28, 2015 as a result of interactions between coronal mass ejections and recurrent streams from coronal holes

    Science.gov (United States)

    Shugay, Yu. S.; Slemzin, V. A.; Rod'kin, D. G.

    2017-11-01

    Coronal sources and parameters of solar wind streams during a strong and prolonged geomagnetic disturbance in June 2015 have been considered. Correspondence between coronal sources and solar wind streams at 1 AU has been determined using an analysis of solar images, catalogs of flares and coronal mass ejections, solar wind parameters including the ionic composition. The sources of disturbances in the considered period were a sequence of five coronal mass ejections that propagated along the recurrent solar wind streams from coronal holes. The observed differences from typical in magnetic and kinetic parameters of solar wind streams have been associated with the interactions of different types of solar wind. The ionic composition has proved to be a good additional marker for highlighting components in a mixture of solar wind streams, which can be associated with different coronal sources.

  5. Charge states of fast heavy ions in solids; target atomic number dependence

    International Nuclear Information System (INIS)

    Shima, Kunihiro

    1985-01-01

    Discussions were carried out on the origin of Z 2 (atomic number) dependent charge states with respect to projectile electron loss and capture process, and on relationship between the Z 2 dependence and that of mean charge states for heavy ions of 1 MeV/u energy region. Present and previously reported results were examined on the equilibrium charge distributions, 9-bar, of 120 MeV 63 Cu, 25 and 40 MeV 35 Cl, 109 MeV Si and 59 MeV F ions. It was clarified that 9-bar became generally higher for lower Z 2 depending on increasing energy, and osillatory behavior with energy-depending amplitude was seen in 9-bar vs Z 2 . Discussions were carrid out on these phenomena and related matters. Z 2 oscillations of 9-bar of fast heavy ions might be due to those of electron capture cross section into projectile K and L vacancies for high and intermediate charge states, respectively. A quantitative interpretation of the Z 2 -dependent 9-bar values is in progress based on collision process and observation of projectile x-ray. The 9-bar value dependency on Z 2 in ion passing foils and decrease of Z 2 oscillation amplitude with increasing collision energy were quite similar to the Z 2 dependence in stopping powers or in effective charge states estimated from stopping powers. But there was some discrepancies in the Z 2 oscillation of 9-bar and that of stopping powers. (Takagi, S.)

  6. LONG-TERM TREND OF SOLAR CORONAL HOLE DISTRIBUTION FROM 1975 TO 2014

    Energy Technology Data Exchange (ETDEWEB)

    Fujiki, K.; Tokumaru, M.; Hayashi, K.; Satonaka, D. [Institute for Space-Earth Environmental Research (ISEE), Nagoya University, Furo-cho, Chikusa, Nagoya Aichi 464-8601 (Japan); Hakamada, K., E-mail: fujiki@isee.nagoya-u.ac.jp [Department of Natural Science and Mathematics, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501 (Japan)

    2016-08-20

    We developed an automated prediction technique for coronal holes using potential magnetic field extrapolation in the solar corona to construct a database of coronal holes appearing from 1975 February to 2015 July (Carrington rotations from 1625 to 2165). Coronal holes are labeled with the location, size, and average magnetic field of each coronal hole on the photosphere and source surface. As a result, we identified 3335 coronal holes and found that the long-term distribution of coronal holes shows a similar pattern known as the magnetic butterfly diagram, and polar/low-latitude coronal holes tend to decrease/increase in the last solar minimum relative to the previous two minima.

  7. Numerical calculation of impurity charge state distributions

    International Nuclear Information System (INIS)

    Crume, E.C.; Arnurius, D.E.

    1977-09-01

    The numerical calculation of impurity charge state distributions using the computer program IMPDYN is discussed. The time-dependent corona atomic physics model used in the calculations is reviewed, and general and specific treatments of electron impact ionization and recombination are referenced. The complete program and two examples relating to tokamak plasmas are given on a microfiche so that a user may verify that his version of the program is working properly. In the discussion of the examples, the corona steady-state approximation is shown to have significant defects when the plasma environment, particularly the electron temperature, is changing rapidly

  8. Engineering of Fermi level by nin diamond junction for control of charge states of NV centers

    Science.gov (United States)

    Murai, T.; Makino, T.; Kato, H.; Shimizu, M.; Murooka, T.; Herbschleb, E. D.; Doi, Y.; Morishita, H.; Fujiwara, M.; Hatano, M.; Yamasaki, S.; Mizuochi, N.

    2018-03-01

    The charge-state control of nitrogen-vacancy (NV) centers in diamond is very important toward its applications because the NV centers undergo stochastic charge-state transitions between the negative charge state (NV-) and the neutral charge state (NV0) of the NV center upon illumination. In this letter, engineering of the Fermi level by a nin diamond junction was demonstrated for the control of the charge state of the NV centers in the intrinsic (i) layer region. By changing the size (d) of the i-layer region between the phosphorus-doped n-type layer regions (nin) from 2 μm to 10 μm, we realized the gradual change in the NV- charge-state population in the i-layer region from 60% to 80% under 532 nm excitation, which can be attributed to the band bending in the i-layer region. Also, we quantitatively simulated the changes in the Fermi level in the i-layer region depending on d with various concentrations of impurities in the i-layer region.

  9. Charge structure of the hadronic final state in deep-inelastic muon-nucleon scattering

    International Nuclear Information System (INIS)

    Arneodo, M.; Ferrero, M.I.; Peroni, C.; Beaufays, J.; Jacholkowska, A.; Kellner, G.; Osborne, A.M.; Bee, C.P.; Bird, I.; Coughlan, J.; Sloan, T.; Braun, H.; Brueck, H.; Drees, J.; Edwards, A.; Krueger, J.; Montgomery, H.E.; Peschel, H.; Pietrzyk, U.; Poetsch, M.; Schneider, A.; Combley, F.; Foster, J.; Whalley, M.; Wheeler, S.; Dreyer, T.; Ernst, T.; Haas, J.; Kabuss, E.M.; Landgraf, U.; Mohr, W.; Rith, K.; Schlagboehmer, A.; Schroeder, T.; Stier, H.E.; Wallucks, W.; Figiel, J.; Gajewski, J.; Janata, F.; Poensgen, B.; Schiemann, H.; Studt, M.; Torre, A. de la; Geddes, N.; Johnson, A.S.; Loken, J.; Long, K.; Renton, P.; Taylor, G.N.; Williams, W.S.C.; Grard, F.; Windmolders, R.

    1988-01-01

    The general charge properties of the hadronic final state produced in μ + p and μ + d interactions at 280 GeV are investigated. Quark charge retention and local charge compensation is observed. The ratio F 2 n /F 2 p of the neutron to proton structure function is derived from the measurement of the average hadronic charge in μd interactions. (orig.)

  10. The X-ray signature of solar coronal mass

    Science.gov (United States)

    Harrison, R. A.; Waggett, P. W.; Bentley, R. D.; Phillips, K. J. H.; Bruner, M.

    1985-01-01

    The coronal response to six solar X-ray flares has been investigated. At a time coincident with the projected onset of the white-light coronal mass ejection associated with each flare, there is a small, discrete soft X-ray enhancement. These enhancements (precursors) precede by typically about 20 m the impulsive phase of the solar flare which is dominant by the time the coronal mass ejection has reached an altitude above 0.5 solar radii. Motions of hot X-ray emitting plasma, during the precursors, which may well be a signature of the mass ejection onsets, are identified. Further investigations have also revealed a second class of X-ray coronal transient, during the main phase of the flare. These appear to be associated with magnetic reconnection above post-flare loop systems.

  11. Ultrafast Charge and Triplet State Formation in Diketopyrrolopyrrole Low Band Gap Polymer/Fullerene Blends: Influence of Nanoscale Morphology of Organic Photovoltaic Materials on Charge Recombination to the Triplet State

    Directory of Open Access Journals (Sweden)

    René M. Williams

    2017-01-01

    Full Text Available Femtosecond transient absorption spectroscopy of thin films of two types of morphologies of diketopyrrolopyrrole low band gap polymer/fullerene-adduct blends is presented and indicates triplet state formation by charge recombination, an important loss channel in organic photovoltaic materials. At low laser fluence (approaching solar intensity charge formation characterized by a 1350 nm band (in ~250 fs dominates in the two PDPP-PCBM blends with different nanoscale morphologies and these charges recombine to form a local polymer-based triplet state on the sub-ns timescale (in ~300 and ~900 ps indicated by an 1100 nm absorption band. The rate of triplet state formation is influenced by the morphology. The slower rate of charge recombination to the triplet state (in ~900 ps belongs to a morphology that results in a higher power conversion efficiency in the corresponding device. Nanoscale morphology not only influences interfacial area and conduction of holes and electrons but also influences the mechanism of intersystem crossing (ISC. We present a model that correlates morphology to the exchange integral and fast and slow mechanisms for ISC (SOCT-ISC and H-HFI-ISC. For the pristine polymer, a flat and unstructured singlet-singlet absorption spectrum (between 900 and 1400 nm and a very minor triplet state formation (5% are observed at low laser fluence.

  12. Introduction of hind foot coronal alignment view

    International Nuclear Information System (INIS)

    Moon, Il Bong; Jeon, Ju Seob; Yoon, Kang Cheol; Choi, Nam Kil; Kim, Seung Kook

    2006-01-01

    Accurate clinical evaluation of the alignment of the calcaneus relative to the tibia in the coronal plane is essential in the evaluation and treatment of hind foot pathologic condition. Previously described standard anteroposterior, lateral, and oblique radiographic methods of the foot or ankle do not demonstrate alignment of the tibia relation to the calcaneus in the coronal plane. The purpose of this study was to introduce hind foot coronal alignment view. Both feet were imaged simultaneously on an elevated, radiolucent foot stand equipment. Both feet stood on a radiolucent platform with equal weight on both feet. Both feet are located foot axis longitudinal perpendicular to the platform. Silhouette tracing around both feet are made, and line is then drawn to bisect the silhouette of the second toe and the outline of the heel. The x-ray beam is angled down approximately 15 .deg. to 20 .deg. This image described tibial axis and medial, lateral tuberosity of calcaneus. Calcaneus do not rotated. The view is showed by talotibial joint space. Although computed tomographic and magnetic resonance imaging techniques are capable of demonstrating coronal hind foot alignment, they lack usefulness in most clinical situations because the foot is imaged in a non-weight bearing position. But hind foot coronal alignment view is obtained for evaluating position changing of inversion, eversion of the hind foot and varus, valgus deformity of calcaneus

  13. Evidence linking coronal mass ejections with interplanetary magnetic clouds

    International Nuclear Information System (INIS)

    Wilson, R.M.; Hildner, E.

    1983-12-01

    Using proxy data for the occurrence of those mass ejections from the solar corona which are directed earthward, we investigate the association between the post-1970 interplanetary magnetic clouds of Klein and Burlaga and coronal mass ejections. The evidence linking magnetic clouds following shocks with coronal mass ejections is striking. Six of nine clouds observed at Earth were preceded an appropriate time earlier by meter-wave type II radio bursts indicative of coronal shock waves and coronal mass ejections occurring near central meridian. During the selected periods when no clouds were detected near Earth, the only type II bursts reported were associated with solar activity near the limbs. Where the proxy solar data to be sought are not so clearly suggested, that is, for clouds preceding interaction regions and clouds within cold magnetic enhancements, the evidence linking the clouds and coronal mass ejections is not as clear proxy data usually suggest many candidate mass-ejection events for each cloud. Overall, the data are consistent with and support the hypothesis suggested by Klein and Burlaga that magnetic clouds observed with spacecraft at 1 AU are manifestations of solar coronal mass ejection transients

  14. Quality of coroner's post-mortems in a UK hospital.

    Science.gov (United States)

    Al Mahdy, Husayn

    2014-01-01

    The aim of this paper was, principally, to look at the coroner's post-mortem report quality regarding adult medical patients admitted to an English hospital; and to compare results with Royal College of Pathologists guidelines. Hospital clinical notes of adult medical patients dying in 2011 and who were referred to the coroner's office to determine the cause of death were scrutinised. Their clinical care was also reviewed. There needs to be a comprehensive approach to coroner's post-mortems such as routinely taking histological and microbiological specimens. Acute adult medical patient care needs to improve. Steps should be taken to ensure that comprehensive coroner's post-mortems are performed throughout the UK, including with routine histological and microbiological specimens examination. Additionally, closer collaboration between clinicians and pathologists needs to occur to improve emergency adult medical patient clinical care. The study highlights inadequacies in coroner's pathology services.

  15. Measurements of EUV coronal holes and open magnetic flux

    Energy Technology Data Exchange (ETDEWEB)

    Lowder, C.; Qiu, J.; Leamon, R. [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Liu, Y., E-mail: clowder@solar.physics.montana.edu [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States)

    2014-03-10

    Coronal holes are regions on the Sun's surface that map the footprints of open magnetic field lines. We have developed an automated routine to detect and track boundaries of long-lived coronal holes using full-disk extreme-ultraviolet (EUV) images obtained by SOHO/EIT, SDO/AIA, and STEREO/EUVI. We measure coronal hole areas and magnetic flux in these holes, and compare the measurements with calculations by the potential field source surface (PFSS) model. It is shown that, from 1996 through 2010, the total area of coronal holes measured with EIT images varies between 5% and 17% of the total solar surface area, and the total unsigned open flux varies between (2-5)× 10{sup 22} Mx. The solar cycle dependence of these measurements is similar to the PFSS results, but the model yields larger hole areas and greater open flux than observed by EIT. The AIA/EUVI measurements from 2010-2013 show coronal hole area coverage of 5%-10% of the total surface area, with significant contribution from low latitudes, which is under-represented by EIT. AIA/EUVI have measured much enhanced open magnetic flux in the range of (2-4)× 10{sup 22} Mx, which is about twice the flux measured by EIT, and matches with the PFSS calculated open flux, with discrepancies in the location and strength of coronal holes. A detailed comparison between the three measurements (by EIT, AIA-EUVI, and PFSS) indicates that coronal holes in low latitudes contribute significantly to the total open magnetic flux. These low-latitude coronal holes are not well measured with either the He I 10830 line in previous studies, or EIT EUV images; neither are they well captured by the static PFSS model. The enhanced observations from AIA/EUVI allow a more accurate measure of these low-latitude coronal holes and their contribution to open magnetic flux.

  16. Charged spin textures over the Moore-Read quantum Hall state

    NARCIS (Netherlands)

    Romers, J.C.; Huijse, L.; Schoutens, K.

    2011-01-01

    We study the composite Charged Spin Texture (CST) over the Moore-Read quantum Hall state that arises when a collection of elementary CSTs are moved to the same location. Following an algebraic approach based on the characteristic pair correlations of the Moore- Read state, we and that the resulting

  17. Anisotropic charged physical models with generalized polytropic equation of state

    Energy Technology Data Exchange (ETDEWEB)

    Nasim, A.; Azam, M. [University of Education, Division of Science and Technology, Lahore (Pakistan)

    2018-01-15

    In this paper, we found the exact solutions of Einstein-Maxwell equations with generalized polytropic equation of state (GPEoS). For this, we consider spherically symmetric object with charged anisotropic matter distribution. We rewrite the field equations into simple form through transformation introduced by Durgapal (Phys Rev D 27:328, 1983) and solve these equations analytically. For the physically acceptability of these solutions, we plot physical quantities like energy density, anisotropy, speed of sound, tangential and radial pressure. We found that all solutions fulfill the required physical conditions. It is concluded that all our results are reduced to the case of anisotropic charged matter distribution with linear, quadratic as well as polytropic equation of state. (orig.)

  18. Case report: pre-eruptive intra-coronal radiolucencies revisited.

    LENUS (Irish Health Repository)

    Counihan, K P

    2012-08-01

    Pre-eruptive intra-coronal radiolucency (PEIR) describes a radiolucent lesion located in the coronal dentine, just beneath the enamel-dentine junction of unerupted teeth. The prevalence of this lesion varies depending on the type and quality of radiographic exposure and age of patients used for assessment. The aetiology of pre-eruptive intra-coronal radiolucent lesions is not fully understood, but published clinical and histological evidence suggest that these lesions are resorptive in nature. Issues around the diagnosis, treatment planning and clinical management of this lesion are explored using previously unreported cases.

  19. COUPLING OF CORONAL AND HELIOSPHERIC MAGNETOHYDRODYNAMIC MODELS: SOLUTION COMPARISONS AND VERIFICATION

    Energy Technology Data Exchange (ETDEWEB)

    Merkin, V. G. [The Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723 (United States); Lionello, R.; Linker, J.; Török, T.; Downs, C. [Predictive Science, Inc., San Diego, CA 92121 (United States); Lyon, J. G., E-mail: slava.merkin@jhuapl.edu [Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States)

    2016-11-01

    Two well-established magnetohydrodynamic (MHD) codes are coupled to model the solar corona and the inner heliosphere. The corona is simulated using the MHD algorithm outside a sphere (MAS) model. The Lyon–Fedder–Mobarry (LFM) model is used in the heliosphere. The interface between the models is placed in a spherical shell above the critical point and allows both models to work in either a rotating or an inertial frame. Numerical tests are presented examining the coupled model solutions from 20 to 50 solar radii. The heliospheric simulations are run with both LFM and the MAS extension into the heliosphere, and use the same polytropic coronal MAS solutions as the inner boundary condition. The coronal simulations are performed for idealized magnetic configurations, with an out-of-equilibrium flux rope inserted into an axisymmetric background, with and without including the solar rotation. The temporal evolution at the inner boundary of the LFM and MAS solutions is shown to be nearly identical, as are the steady-state background solutions, prior to the insertion of the flux rope. However, after the coronal mass ejection has propagated through the significant portion of the simulation domain, the heliospheric solutions diverge. Additional simulations with different resolution are then performed and show that the MAS heliospheric solutions approach those of LFM when run with progressively higher resolution. Following these detailed tests, a more realistic simulation driven by the thermodynamic coronal MAS is presented, which includes solar rotation and an azimuthally asymmetric background and extends to the Earth’s orbit.

  20. Nonlinear Force-free Coronal Magnetic Stereoscopy

    Energy Technology Data Exchange (ETDEWEB)

    Chifu, Iulia; Wiegelmann, Thomas; Inhester, Bernd, E-mail: chifu@mps.mpg.de [Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany)

    2017-03-01

    Insights into the 3D structure of the solar coronal magnetic field have been obtained in the past by two completely different approaches. The first approach are nonlinear force-free field (NLFFF) extrapolations, which use photospheric vector magnetograms as boundary condition. The second approach uses stereoscopy of coronal magnetic loops observed in EUV coronal images from different vantage points. Both approaches have their strengths and weaknesses. Extrapolation methods are sensitive to noise and inconsistencies in the boundary data, and the accuracy of stereoscopy is affected by the ability of identifying the same structure in different images and by the separation angle between the view directions. As a consequence, for the same observational data, the 3D coronal magnetic fields computed with the two methods do not necessarily coincide. In an earlier work (Paper I) we extended our NLFFF optimization code by including stereoscopic constrains. The method was successfully tested with synthetic data, and within this work, we apply the newly developed code to a combined data set from SDO /HMI, SDO /AIA, and the two STEREO spacecraft. The extended method (called S-NLFFF) contains an additional term that monitors and minimizes the angle between the local magnetic field direction and the orientation of the 3D coronal loops reconstructed by stereoscopy. We find that when we prescribe the shape of the 3D stereoscopically reconstructed loops, the S-NLFFF method leads to a much better agreement between the modeled field and the stereoscopically reconstructed loops. We also find an appreciable decrease by a factor of two in the angle between the current and the magnetic field. This indicates the improved quality of the force-free solution obtained by S-NLFFF.

  1. A Battery Charger and State of Charge Indicator

    Science.gov (United States)

    Latos, T. S.

    1984-01-01

    A battery charger which has a full wave rectifier in series with a transformer isolated 20 kHz dc-dc converter with high frequency switches, which are programmed to actively shape the input dc line current to be a mirror image of the ac line voltage is discussed. The power circuit operates at 2 kW peak and 1 kW average power. The BC/SCI has two major subsystems: (1) the battery charger power electronics with its controls; and (2) a microcomputer subsystem which is used to acquire battery terminal data and exercise the state of charge software programs. The state of charge definition employed is the energy remaining in the battery when extracted at a 10 kW rate divided by the energy capacity of a fully charged new battery. The battery charger circuit is an isolated boost converter operating at an internal frequency of 20 kHz. The switches selected for the battery charger are the single most important item in determining its efficiency. The combination of voltage and current requirements dictate the use of high power NPN Darlington switching transistors. The power circuit topology is a three switch design which utilizes a power FET on the center tap of the isolation transformer and the power Darlingtons on each of the two ends. An analog control system is employed to accomplish active input current waveshaping as well as the necessary regulation.

  2. Coronal Loops: Evolving Beyond the Isothermal Approximation

    Science.gov (United States)

    Schmelz, J. T.; Cirtain, J. W.; Allen, J. D.

    2002-05-01

    Are coronal loops isothermal? A controversy over this question has arisen recently because different investigators using different techniques have obtained very different answers. Analysis of SOHO-EIT and TRACE data using narrowband filter ratios to obtain temperature maps has produced several key publications that suggest that coronal loops may be isothermal. We have constructed a multi-thermal distribution for several pixels along a relatively isolated coronal loop on the southwest limb of the solar disk using spectral line data from SOHO-CDS taken on 1998 Apr 20. These distributions are clearly inconsistent with isothermal plasma along either the line of sight or the length of the loop, and suggested rather that the temperature increases from the footpoints to the loop top. We speculated originally that these differences could be attributed to pixel size -- CDS pixels are larger, and more `contaminating' material would be expected along the line of sight. To test this idea, we used CDS iron line ratios from our data set to mimic the isothermal results from the narrowband filter instruments. These ratios indicated that the temperature gradient along the loop was flat, despite the fact that a more complete analysis of the same data showed this result to be false! The CDS pixel size was not the cause of the discrepancy; rather, the problem lies with the isothermal approximation used in EIT and TRACE analysis. These results should serve as a strong warning to anyone using this simplistic method to obtain temperature. This warning is echoed on the EIT web page: ``Danger! Enter at your own risk!'' In other words, values for temperature may be found, but they may have nothing to do with physical reality. Solar physics research at the University of Memphis is supported by NASA grant NAG5-9783. This research was funded in part by the NASA/TRACE MODA grant for Montana State University.

  3. Target life time of laser ion source for low charge state ion production

    Energy Technology Data Exchange (ETDEWEB)

    Kanesue,T.; Tamura, J.; Okamura, M.

    2008-06-23

    Laser ion source (LIS) produces ions by irradiating pulsed high power laser shots onto the solid state target. For the low charge state ion production, laser spot diameter on the target can be over several millimeters using a high power laser such as Nd:YAG laser. In this case, a damage to the target surface is small while there is a visible crater in case of the best focused laser shot for high charge state ion production (laser spot diameter can be several tens of micrometers). So the need of target displacement after each laser shot to use fresh surface to stabilize plasma is not required for low charge state ion production. We tested target lifetime using Nd:YAG laser with 5 Hz repetition rate. Also target temperature and vacuum condition were recorded during experiment. The feasibility of a long time operation was verified.

  4. Charged boson bound states in the kerr-newman metric

    International Nuclear Information System (INIS)

    Li Yuanjie; Zhang Duanming

    1986-01-01

    Charged boson bound states in Kerr-Newman metric are discussed. It is found that massless boson cannot be attracted by Kerr-Newman black hole to form bound states. For the massive boson, the condition of the nonbound states when 0 2 - Q 2 and both the condition and wave functions of the bound states when a = √M 2 - Q 2 are obtained. The energy mode of the bound states is single, E = (m√M 2 - Q 2 + eQM)/(2M 2 - Q 2 ). When Q = 0 or e = 0, the conclusion is in agreement with that of Zhang Shiwei and Su Rukeng

  5. Magnetic Topology of Coronal Hole Linkages

    Science.gov (United States)

    Titov, V. S.; Mikic, Z.; Linker, J. A.; Lionello, R.; Antiochos, S. K.

    2010-01-01

    In recent work, Antiochos and coworkers argued that the boundary between the open and closed field regions on the Sun can be extremely complex with narrow corridors of open ux connecting seemingly disconnected coronal holes from the main polar holes, and that these corridors may be the sources of the slow solar wind. We examine, in detail, the topology of such magnetic configurations using an analytical source surface model that allows for analysis of the eld with arbitrary resolution. Our analysis reveals three important new results: First, a coronal hole boundary can join stably to the separatrix boundary of a parasitic polarity region. Second, a single parasitic polarity region can produce multiple null points in the corona and, more important, separator lines connecting these points. Such topologies are extremely favorable for magnetic reconnection, because it can now occur over the entire length of the separators rather than being con ned to a small region around the nulls. Finally, the coronal holes are not connected by an open- eld corridor of finite width, but instead are linked by a singular line that coincides with the separatrix footprint of the parasitic polarity. We investigate how the topological features described above evolve in response to motion of the parasitic polarity region. The implications of our results for the sources of the slow solar wind and for coronal and heliospheric observations are discussed.

  6. PHYSICAL CONDITIONS OF CORONAL PLASMA AT THE TRANSIT OF A SHOCK DRIVEN BY A CORONAL MASS EJECTION

    Energy Technology Data Exchange (ETDEWEB)

    Susino, R.; Bemporad, A.; Mancuso, S., E-mail: susino@oato.inaf.it [INAF–Turin Astrophysical Observatory, via Osservatorio 20, I-10025 Pino Torinese (Italy)

    2015-10-20

    We report here on the determination of plasma physical parameters across a shock driven by a coronal mass ejection using white light (WL) coronagraphic images and radio dynamic spectra (RDS). The event analyzed here is the spectacular eruption that occurred on 2011 June 7, a fast CME followed by the ejection of columns of chromospheric plasma, part of them falling back to the solar surface, associated with a M2.5 flare and a type-II radio burst. Images acquired by the Solar and Heliospheric Observatory/LASCO coronagraphs (C2 and C3) were employed to track the CME-driven shock in the corona between 2–12 R{sub ⊙} in an angular interval of about 110°. In this interval we derived two-dimensional (2D) maps of electron density, shock velocity, and shock compression ratio, and we measured the shock inclination angle with respect to the radial direction. Under plausible assumptions, these quantities were used to infer 2D maps of shock Mach number M{sub A} and strength of coronal magnetic fields at the shock's heights. We found that in the early phases (2–4 R{sub ⊙}) the whole shock surface is super-Alfvénic, while later on (i.e., higher up) it becomes super-Alfvénic only at the nose. This is in agreement with the location for the source of the observed type-II burst, as inferred from RDS combined with the shock kinematic and coronal densities derived from WL. For the first time, a coronal shock is used to derive a 2D map of the coronal magnetic field strength over intervals of 10 R{sub ⊙} altitude and ∼110° latitude.

  7. Energy released by the interaction of coronal magnetic fields

    International Nuclear Information System (INIS)

    Sheeley, N.R. Jr.

    1976-01-01

    Comparisons between coronal spectroheliograms and photospheric magnetograms are presented to support the idea that as coronal magnetic fields interact, a process of field line reconnection usually takes place as a natural way of preventing magnetic stresses from building up in the lower corona. This suggests that the energy which would have been stored in stressed fields in continuously released as kinetic energy of material being driven aside to make way for the reconnecting fields. However, this kinetic energy is negligible compared to the thermal energy of the coronal plasma. Therefore, it appears that these slow adjustments of coronal magnetic fields cannot account for even the normal heating of the corona, much less the energetic events associated with solar flares. (Auth.)

  8. High-Power Collective Charging of a Solid-State Quantum Battery

    Science.gov (United States)

    Ferraro, Dario; Campisi, Michele; Andolina, Gian Marcello; Pellegrini, Vittorio; Polini, Marco

    2018-03-01

    Quantum information theorems state that it is possible to exploit collective quantum resources to greatly enhance the charging power of quantum batteries (QBs) made of many identical elementary units. We here present and solve a model of a QB that can be engineered in solid-state architectures. It consists of N two-level systems coupled to a single photonic mode in a cavity. We contrast this collective model ("Dicke QB"), whereby entanglement is genuinely created by the common photonic mode, to the one in which each two-level system is coupled to its own separate cavity mode ("Rabi QB"). By employing exact diagonalization, we demonstrate the emergence of a quantum advantage in the charging power of Dicke QBs, which scales like √{N } for N ≫1 .

  9. The nature of micro CMEs within coronal holes

    Science.gov (United States)

    Bothmer, Volker; Nistico, Giuseppe; Zimbardo, Gaetano; Patsourakos, Spiros; Bosman, Eckhard

    Whilst investigating the origin and characteristics of coronal jets and large-scale CMEs identi-fied in data from the SECCHI (Sun Earth Connection Coronal and Heliospheric Investigation) instrument suites on board the two STEREO satellites, we discovered transient events that originated in the low corona with a morphology resembling that of typical three-part struc-tured coronal mass ejections (CMEs). However, the CMEs occurred on considerably smaller spatial scales. In this presentation we show evidence for the existence of small-scale CMEs from inside coronal holes and present quantitative estimates of their speeds and masses. We interprete the origin and evolution of micro CMEs as a natural consequence of the emergence of small-scale magnetic bipoles related to the Sun's ever changing photospheric magnetic flux on various scales and their interactions with the ambient plasma and magnetic field. The analysis of CMEs is performed within the framework of the EU Erasmus and FP7 SOTERIA projects.

  10. Coronal Heating Observed with Hi-C

    Science.gov (United States)

    Winebarger, Amy R.

    2013-01-01

    The recent launch of the High-Resolution Coronal Imager (Hi-C) as a sounding rocket has offered a new, different view of the Sun. With approx 0.3" resolution and 5 second cadence, Hi-C reveals dynamic, small-scale structure within a complicated active region, including coronal braiding, reconnection regions, Alfven waves, and flows along active region fans. By combining the Hi-C data with other available data, we have compiled a rich data set that can be used to address many outstanding questions in solar physics. Though the Hi-C rocket flight was short (only 5 minutes), the added insight of the small-scale structure gained from the Hi-C data allows us to look at this active region and other active regions with new understanding. In this talk, I will review the first results from the Hi-C sounding rocket and discuss the impact of these results on the coronal heating problem.

  11. Forward Modeling of a Coronal Cavity

    Science.gov (United States)

    Kucera, T. A.; Gibson, S. E.; Schmit, D. J.

    2011-01-01

    We apply a forward model of emission from a coronal cavity in an effort to determine the temperature and density distribution in the cavity. Coronal cavities are long, low-density structures located over filament neutral lines and are often seen as dark elliptical features at the solar limb in white light, EUV and X-rays. When these structures erupt they form the cavity portions of CMEs The model consists of a coronal streamer model with a tunnel-like cavity with elliptical cross-section and a Gaussian variation of height along the tunnel length. Temperature and density can be varied as a function of altitude both in the cavity and streamer. We apply this model to a cavity observed in Aug. 2007 by a wide array of instruments including Hinode/EIS, STEREO/EUVI and SOHO/EIT. Studies such as these will ultimately help us understand the the original structures which erupt to become CMEs and ICMES, one of the prime Solar Orbiter objectives.

  12. SUNQUAKE GENERATION BY CORONAL MAGNETIC RESTRUCTURING

    Energy Technology Data Exchange (ETDEWEB)

    Russell, A. J. B.; Mooney, M. K. [School of Science and Engineering, University of Dundee, Dundee DD1 4HN (United Kingdom); Leake, J. E. [Naval Research Laboratory, Washington, DC 20375 (United States); Hudson, H. S. [Space Sciences Lab, University of California Berkeley, Berkeley, CA 94720 (United States)

    2016-11-01

    Sunquakes are the surface signatures of acoustic waves in the Sun’s interior that are produced by some but not all flares and coronal mass ejections (CMEs). This paper explores a mechanism for sunquake generation by the changes in magnetic field that occur during flares and CMEs, using MHD simulations with a semiempirical FAL-C atmosphere to demonstrate the generation of acoustic waves in the interior in response to changing magnetic tilt in the corona. We find that Alfvén–sound resonance combined with the ponderomotive force produces acoustic waves in the interior with sufficient energy to match sunquake observations when the magnetic field angle changes of the order of 10° in a region where the coronal field strength is a few hundred gauss or more. The most energetic sunquakes are produced when the coronal field is strong, while the variation of magnetic field strength with height and the timescale of the change in tilt are of secondary importance.

  13. SUNQUAKE GENERATION BY CORONAL MAGNETIC RESTRUCTURING

    International Nuclear Information System (INIS)

    Russell, A. J. B.; Mooney, M. K.; Leake, J. E.; Hudson, H. S.

    2016-01-01

    Sunquakes are the surface signatures of acoustic waves in the Sun’s interior that are produced by some but not all flares and coronal mass ejections (CMEs). This paper explores a mechanism for sunquake generation by the changes in magnetic field that occur during flares and CMEs, using MHD simulations with a semiempirical FAL-C atmosphere to demonstrate the generation of acoustic waves in the interior in response to changing magnetic tilt in the corona. We find that Alfvén–sound resonance combined with the ponderomotive force produces acoustic waves in the interior with sufficient energy to match sunquake observations when the magnetic field angle changes of the order of 10° in a region where the coronal field strength is a few hundred gauss or more. The most energetic sunquakes are produced when the coronal field is strong, while the variation of magnetic field strength with height and the timescale of the change in tilt are of secondary importance.

  14. A contemporary view of coronal heating.

    Science.gov (United States)

    Parnell, Clare E; De Moortel, Ineke

    2012-07-13

    Determining the heating mechanism (or mechanisms) that causes the outer atmosphere of the Sun, and many other stars, to reach temperatures orders of magnitude higher than their surface temperatures has long been a key problem. For decades, the problem has been known as the coronal heating problem, but it is now clear that 'coronal heating' cannot be treated or explained in isolation and that the heating of the whole solar atmosphere must be studied as a highly coupled system. The magnetic field of the star is known to play a key role, but, despite significant advancements in solar telescopes, computing power and much greater understanding of theoretical mechanisms, the question of which mechanism or mechanisms are the dominant supplier of energy to the chromosphere and corona is still open. Following substantial recent progress, we consider the most likely contenders and discuss the key factors that have made, and still make, determining the actual (coronal) heating mechanism (or mechanisms) so difficult.

  15. Tracking excited-state charge and spin dynamics in iron coordination complexes

    DEFF Research Database (Denmark)

    Zhang, Wenkai; Alonso-Mori, Roberto; Bergmann, Uwe

    2014-01-01

    to spin state, can elucidate the spin crossover dynamics of [Fe(2,2'-bipyridine)(3)](2+) on photoinduced metal-to-ligand charge transfer excitation. We are able to track the charge and spin dynamics, and establish the critical role of intermediate spin states in the crossover mechanism. We anticipate......Crucial to many light-driven processes in transition metal complexes is the absorption and dissipation of energy by 3d electrons(1-4). But a detailed understanding of such non-equilibrium excited-state dynamics and their interplay with structural changes is challenging: a multitude of excited...... states and possible transitions result in phenomena too complex to unravel when faced with the indirect sensitivity of optical spectroscopy to spin dynamics(5) and the flux limitations of ultrafast X-ray sources(6,7). Such a situation exists for archetypal poly-pyridyl iron complexes, such as [Fe(2...

  16. Deriving the coronal hole electron temperature: electron density dependent ionization / recombination considerations

    International Nuclear Information System (INIS)

    Doyle, John Gerard; Perez-Suarez, David; Singh, Avninda; Chapman, Steven; Bryans, Paul; Summers, Hugh; Savin, Daniel Wolf

    2010-01-01

    Comparison of appropriate theoretically derived line ratios with observational data can yield estimates of a plasma's physical parameters, such as electron density or temperature. The usual practice in the calculation of the line ratio is the assumption of excitation by electrons/protons followed by radiative decay. Furthermore, it is normal to use the so-called coronal approximation, i.e. one only considers ionization and recombination to and from the ground-state. A more accurate treatment is to include ionization/recombination to and from metastable levels. Here, we apply this to two lines from adjacent ionization stages, Mg IX 368 A and Mg X 625 A, which has been shown to be a very useful temperature diagnostic. At densities typical of coronal hole conditions, the difference between the electron temperature derived assuming the zero density limit compared with the electron density dependent ionization/recombination is small. This, however, is not the case for flares where the electron density is orders of magnitude larger. The derived temperature for the coronal hole at solar maximum is around 1.04 MK compared to just below 0.82 MK at solar minimum.

  17. Charge orders in organic charge-transfer salts

    International Nuclear Information System (INIS)

    Kaneko, Ryui; Valentí, Roser; Tocchio, Luca F; Becca, Federico

    2017-01-01

    Motivated by recent experimental suggestions of charge-order-driven ferroelectricity in organic charge-transfer salts, such as κ -(BEDT-TTF) 2 Cu[N(CN) 2 ]Cl, we investigate magnetic and charge-ordered phases that emerge in an extended two-orbital Hubbard model on the anisotropic triangular lattice at 3/4 filling. This model takes into account the presence of two organic BEDT-TTF molecules, which form a dimer on each site of the lattice, and includes short-range intramolecular and intermolecular interactions and hoppings. By using variational wave functions and quantum Monte Carlo techniques, we find two polar states with charge disproportionation inside the dimer, hinting to ferroelectricity. These charge-ordered insulating phases are stabilized in the strongly correlated limit and their actual charge pattern is determined by the relative strength of intradimer to interdimer couplings. Our results suggest that ferroelectricity is not driven by magnetism, since these polar phases can be stabilized also without antiferromagnetic order and provide a possible microscopic explanation of the experimental observations. In addition, a conventional dimer-Mott state (with uniform density and antiferromagnetic order) and a nonpolar charge-ordered state (with charge-rich and charge-poor dimers forming a checkerboard pattern) can be stabilized in the strong-coupling regime. Finally, when electron–electron interactions are weak, metallic states appear, with either uniform charge distribution or a peculiar 12-site periodicity that generates honeycomb-like charge order. (paper)

  18. High charge state metal ion production in vacuum arc ion sources

    International Nuclear Information System (INIS)

    Brown, I.G.; Anders, A.; Anders, S.

    1994-01-01

    The vacuum arc is a rich source of highly ionized metal plasma that can be used to make a high current metal ion source. Vacuum arc ion sources have been developed for a range of applications including ion implantation for materials surface modification, particle accelerator injection for fundamental nuclear physics research, and other fundamental and applied purposes. Typically the source is repetitively pulsed with pulse length of order a millisecond and duty cycle or order 1% and operation of a dc embodiment has been demonstrated also. Beams have been produced from over 50 of the solid metals of the periodic table, with mean ion energy up to several hundred keV and with peak (pulsed) beam current up to several amperes. The ion charge state distribution has been extensively studied. Ion spectra have been measured for a wide range of metallic cathode materials, including Li, C, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ge, Sr, Y, Zr, Nb, Mo, Pd, Ag, Cd, In, Sn, Sb, Ba, La, Ce, Pr, Nd, Sm, Gd, Dy, Ho, Er, Tm, Yb, Hf, Ta, W, Ir, Pt, Au, Pb, Bi, Th and U, as well as compound and alloy cathode materials such as TiC, SiC, UC, PbS, brass, and stainless steel. The ions generated are in general multiply-stripped with a mean charge state of from 1 to 3, depending on the particular metal species, and the charge state distribution can have components from Q = 1+ to 6+. Here the authors review the characteristics of vacuum arc ion sources from the perspective of their high charge state metal ion production

  19. CME Interaction with Coronal Holes and Their Interplanetary Consequences

    Science.gov (United States)

    Gopalswamy, N.; Makela, P.; Xie, H.; Akiyama, S.; Yashiro, S.

    2008-01-01

    A significant number of interplanetary (IP) shocks (-17%) during cycle 23 were not followed by drivers. The number of such "driverless" shocks steadily increased with the solar cycle with 15%, 33%, and 52% occurring in the rise, maximum, and declining phase of the solar cycle. The solar sources of 15% of the driverless shocks were very close the central meridian of the Sun (within approx.15deg), which is quite unexpected. More interestingly, all the driverless shocks with their solar sources near the solar disk center occurred during the declining phase of solar cycle 23. When we investigated the coronal environment of the source regions of driverless shocks, we found that in each case there was at least one coronal hole nearby suggesting that the coronal holes might have deflected the associated coronal mass ejections (CMEs) away from the Sun-Earth line. The presence of abundant low-latitude coronal holes during the declining phase further explains why CMEs originating close to the disk center mimic the limb CMEs, which normally lead to driverless shocks due to purely geometrical reasons. We also examined the solar source regions of shocks with drivers. For these, the coronal holes were located such that they either had no influence on the CME trajectories. or they deflected the CMEs towards the Sun-Earth line. We also obtained the open magnetic field distribution on the Sun by performing a potential field source surface extrapolation to the corona. It was found that the CMEs generally move away from the open magnetic field regions. The CME-coronal hole interaction must be widespread in the declining phase, and may have a significant impact on the geoeffectiveness of CMEs.

  20. The Prospect for Detecting Stellar Coronal Mass Ejections

    Science.gov (United States)

    Osten, Rachel A.; Crosley, Michael Kevin

    2018-06-01

    The astrophysical study of mass loss, both steady-state and transient, on the cool half of the HR diagram has implications bothfor the star itself and the conditions created around the star that can be hospitable or inimical to supporting life. Recent results from exoplanet studies show that planets around M dwarfs are exceedingly common, which together with the commonality of M dwarfs in our galaxy make this the dominant mode of star and planet configurations. The closeness of the exoplanets to the parent M star motivate a comprehensive understanding of habitability for these systems. Radio observations provide the most clear signature of accelerated particles and shocks in stars arising as the result of MHD processes in the stellar outer atmosphere. Stellar coronal mass ejections have not been conclusively detected, despite the ubiquity with which their radiative counterparts in an eruptive event (stellar flares) have. I will review some of the different observational methods which have been used and possibly could be used in the future in the stellar case, emphasizing some of the difficulties inherent in such attempts. I will provide a framework for interpreting potential transient stellar mass loss in light of the properties of flares known to occur on magnetically active stars. This uses a physically motivated way to connect the properties of flares and coronal mass ejections and provides a testable hypothesis for observing or constraining transient stellar mass loss. I will describe recent results using radio observations to detect stellar coronal mass ejections, and what those results imply about transient stellar mass loss. I will provide some motivation for what could be learned in this topic from space-based low frequency radio experiments.

  1. The COronal Solar Magnetism Observatory (COSMO) Large Aperture Coronagraph

    Science.gov (United States)

    Tomczyk, Steve; Gallagher, Dennis; Wu, Zhen; Zhang, Haiying; Nelson, Pete; Burkepile, Joan; Kolinksi, Don; Sutherland, Lee

    2013-04-01

    The COSMO is a facility dedicated to observing coronal and chromospheric magnetic fields. It will be located on a mountaintop in the Hawaiian Islands and will replace the current Mauna Loa Solar Observatory (MLSO). COSMO will provide unique observations of the global coronal magnetic fields and its environment to enhance the value of data collected by other observatories on the ground (e.g. SOLIS, BBO NST, Gregor, ATST, EST, Chinese Giant Solar Telescope, NLST, FASR) and in space (e.g. SDO, Hinode, SOHO, GOES, STEREO, Solar-C, Solar Probe+, Solar Orbiter). COSMO will employ a fleet of instruments to cover many aspects of measuring magnetic fields in the solar atmosphere. The dynamics and energy flow in the corona are dominated by magnetic fields. To understand the formation of CMEs, their relation to other forms of solar activity, and their progression out into the solar wind requires measurements of coronal magnetic fields. The large aperture coronagraph, the Chromospheric and Prominence Magnetometer and the K-Coronagraph form the COSMO instrument suite to measure magnetic fields and the polarization brightness of the low corona used to infer electron density. The large aperture coronagraph will employ a 1.5 meter fuse silica singlet lens, birefringent filters, and a spectropolarimeter to cover fields of view of up to 1 degree. It will observe the corona over a wide range of emission lines from 530.3 nm through 1083.0 nm allowing for magnetic field measurements over a wide range of coronal temperatures (e.g. FeXIV at 530.3 nm, Fe X at 637.4 nm, Fe XIII at 1074.7 and 1079.8 nm. These lines are faint and require the very large aperture. NCAR and NSF have provided funding to bring the large aperture coronagraph to a preliminary design review state by the end of 2013. As with all data from Mauna Loa, the data products from COSMO will be available to the community via the Mauna Loa website: http://mlso.hao.ucar.edu

  2. A Summary of Recent Experimental Research on Ion Energy and Charge States of Pulsed Vacuum Arcs

    International Nuclear Information System (INIS)

    Oks, Efim M.; Yushkov, Georgy Yu.; Anders, Andre

    2008-01-01

    The paper reviews the results of vacuum arc experimental investigations made collaboratively by research groups from Berkeley and Tomsk over the last two years, i.e. since the last ISDEIV in 2006. Vacuum arc plasma of various metals was produced in pulses of a few hundred microseconds duration, and the research focused on three topics: (i) the energy distribution functions for different ion charge states, (ii) the temporal development of the ion charge state distribution, and (iii) the evolution of the mean directed ion velocities during plasma expansion. A combined quadruple mass-to-charge and energy analyzer (EQP by HIDEN Ltd) and a time-of-flight spectrometer were employed. Cross-checking data by those complimentary techniques helped to avoid possible pitfalls in interpretation. It was found that the ion energy distribution functions in the plasma were independent of the ion charge state, which implies that the energy distribution on a substrate are not equal to due to acceleration in the substrate's sheath. In pulsed arc mode, the individual ion charge states fractions showed changes leading to a decrease of the mean charge state toward a steady-state value. This decrease can be reduced by lower arc current, higher pulse repetition rate and reduced length of the discharge gap. It was also found that the directed ion velocity slightly decreased as the plasma expanded into vacuum

  3. Unusual inhomogeneous microstructures in charge glass state of PbCrO3

    Science.gov (United States)

    Kurushima, Kosuke; Tsukasaki, Hirofumi; Ogata, Takahiro; Sakai, Yuki; Azuma, Masaki; Ishii, Yui; Mori, Shigeo

    2018-05-01

    We investigated the microstructures and local structures of perovskite PbCrO3, which shows a metal-to-insulator transition and a 9.8% volume collapse, by electron diffraction, high-resolution transmission electron microscopy (TEM), and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). It is revealed that the charge glass state is characterized by the unique coexistence of the crystalline state with a cubic symmetry on average and the noncrystalline state. HAADF-STEM observation at atomic resolution revealed that Pb ions were displaced from the ideal A site position of the cubic perovskite structure, which gives rise to characteristic diffuse scatterings around the fundamental Bragg reflections. These structural inhomogeneities are crucial to the understanding of the unique physical properties in the charge glass state of PbCrO3.

  4. Effect of dielectronic recombination on the charge-state distribution ...

    Indian Academy of Sciences (India)

    Abstract. The effect of dielectronic recombination in determining charge-state distribu- tion and radiative emission from a laser-produced carbon plasma has been investigated in the collisional radiative ionization equilibrium. It is observed that the relative abundances of different ions in the plasma, and soft X-ray emission ...

  5. INTERCHANGE RECONNECTION AND CORONAL HOLE DYNAMICS

    International Nuclear Information System (INIS)

    Edmondson, J. K.; Antiochos, S. K.; DeVore, C. R.; Lynch, B. J.; Zurbuchen, T. H.

    2010-01-01

    We investigate the effect of magnetic reconnection between open and closed fields, often referred to as 'interchange' reconnection, on the dynamics and topology of coronal hole boundaries. The most important and most prevalent three-dimensional topology of the interchange process is that of a small-scale bipolar magnetic field interacting with a large-scale background field. We determine the evolution of such a magnetic topology by numerical solution of the fully three-dimensional MHD equations in spherical coordinates. First, we calculate the evolution of a small-scale bipole that initially is completely inside an open field region and then is driven across a coronal hole boundary by photospheric motions. Next the reverse situation is calculated in which the bipole is initially inside the closed region and driven toward the coronal hole boundary. In both cases, we find that the stress imparted by the photospheric motions results in deformation of the separatrix surface between the closed field of the bipole and the background field, leading to rapid current sheet formation and to efficient reconnection. When the bipole is inside the open field region, the reconnection is of the interchange type in that it exchanges open and closed fields. We examine, in detail, the topology of the field as the bipole moves across the coronal hole boundary and find that the field remains well connected throughout this process. Our results, therefore, provide essential support for the quasi-steady models of the open field, because in these models the open and closed flux are assumed to remain topologically distinct as the photosphere evolves. Our results also support the uniqueness hypothesis for open field regions as postulated by Antiochos et al. On the other hand, the results argue against models in which open flux is assumed to diffusively penetrate deeply inside the closed field region under a helmet streamer. We discuss the implications of this work for coronal observations.

  6. Communicating with the coroner: how religion, culture, and family concerns may influence autopsy decision making.

    Science.gov (United States)

    Carpenter, Belinda; Adkins, Glenda; Barnes, Michael; Naylor, Charles; Begum, Nelufa

    2011-04-01

    Based on coronial data gathered in the state of Queensland in 2004, this article reviews how a change in legislation may have impacted autopsy decision making by coroners. More specifically, the authors evaluated whether the requirement that coronial autopsy orders specify the level of invasiveness of an autopsy to be performed by a pathologist was affected by the further requirement that coroners take into consideration a known religion, culture, and/or raised family concern before making such an order. Preliminary data reveal that the cultural status of the deceased did not affect coronial autopsy decision making. However, a known religion with a proscription against autopsy and a raised family concern appeared to be taken into account by coroners when making autopsy decisions and tended to decrease the invasiveness of the autopsy ordered from a full internal examination to either a partial internal examination or an external-only examination of the body. The impact of these findings is briefly discussed.

  7. Excited State Structural Dynamics of Carotenoids and ChargeTransfer Systems

    Energy Technology Data Exchange (ETDEWEB)

    Van Tassle, Aaron Justin [Univ. of California, Berkeley, CA (United States)

    2006-01-01

    This dissertation describes the development andimplementation of a visible/near infrared pump/mid-infrared probeapparatus. Chapter 1 describes the background and motivation ofinvestigating optically induced structural dynamics, paying specificattention to solvation and the excitation selection rules of highlysymmetric molecules such as carotenoids. Chapter 2 describes thedevelopment and construction of the experimental apparatus usedthroughout the remainder of this dissertation. Chapter 3 will discuss theinvestigation of DCM, a laser dye with a fluorescence signal resultingfrom a charge transfer state. By studying the dynamics of DCM and of itsmethyl deuterated isotopomer (an otherwise identical molecule), we areable to investigate the origins of the charge transfer state and provideevidence that it is of the controversial twisted intramolecular (TICT)type. Chapter 4 introduces the use of two-photon excitation to the S1state, combined with one-photon excitation to the S2 state of thecarotenoid beta-apo-8'-carotenal. These 2 investigations show evidencefor the formation of solitons, previously unobserved in molecular systemsand found only in conducting polymers Chapter 5 presents an investigationof the excited state dynamics of peridinin, the carotenoid responsiblefor the light harvesting of dinoflagellates. This investigation allowsfor a more detailed understanding of the importance of structuraldynamics of carotenoids in light harvesting.

  8. An Estimate of Solar Wind Velocity Profiles in a Coronal Hole and a Coronal Streamer Area (6-40 R(radius symbol)

    Science.gov (United States)

    Patzold, M.; Tsurutani, B. T.; Bird, M. K.

    1995-01-01

    Total electron content data obtained from the Ulysses Solar Corona Experiment (SCE) in 1991 were used to select two data sets, one associated with a coronal hole and the other with coronal streamer crossings. (This is largely equatorial data shortly after solar maximum.) The solar wind velocity profile is estimated for these areas.

  9. ARCHITECTURE OF A CHARGE-TRANSFER STATE REGULATING LIGHT HARVESTING IN A PLANT ANTENNA PROTEIN

    Energy Technology Data Exchange (ETDEWEB)

    Fleming, Graham; Ahn, Tae Kyu; Avenson, Thomas J.; Ballottari, Matteo; Cheng, Yuan-Chung; Niyogi, Krishna K.; Bassi, Roberto; Fleming, Graham R.

    2008-04-02

    Energy-dependent quenching of excess absorbed light energy (qE) is a vital mechanism for regulating photosynthetic light harvesting in higher plants. All of the physiological characteristics of qE have been positively correlated with charge-transfer between coupled chlorophyll and zeaxanthin molecules in the light-harvesting antenna of photosystem II (PSII). In this work, we present evidence for charge-transfer quenching in all three of the individual minor antenna complexes of PSII (CP29, CP26, and CP24), and we conclude that charge-transfer quenching in CP29 involves a de-localized state of an excitonically coupled chlorophyll dimer. We propose that reversible conformational changes in CP29 can `tune? the electronic coupling between the chlorophylls in this dimer, thereby modulating the energy of the chlorophylls-zeaxanthin charge-transfer state and switching on and off the charge-transfer quenching during qE.

  10. Production, transport and charge capture measurements of highly charged recoil ions

    International Nuclear Information System (INIS)

    Trebus, U.E.

    1989-01-01

    An experiment is described to study highly charged recoil ions on-line to the heavy accelerator UNILAC at GSI. The highly charged recoil ions are produced by heavy-ion bombardment of a gas target. Subsequently the slow highly charged recoil ions are extracted from the ionization volume, and guided through a beam transport line to a Wien filter for charge state selection and to a collision region to study charge transfer processes. Several experiments were carried out to show the efficient charge state separation. Charge states up to q = 15 were observed. When using a retarding field analyzer cross sections for single electron capture were determined for different charge states of Xe q+ for q = 4 to 11 and He gas. The experiments demonstrated increasing charge transfer cross sections with increasing charge state q and indicated the effect of near resonant charge capture for q = 6. The flexible data acquisition system used, is described and other future experiments, such as for instance in flight ion-trapping are indicated in the appendix

  11. Production, transport and charge capture measurements of highly charged recoil ions

    International Nuclear Information System (INIS)

    Trebus, U.E.

    1989-05-01

    An experiment is described to study highly charged recoil ions on-line to the heavy ion accelerator UNILAC at GSI. The highly charged recoil ions are produced by heavy ion bombardment of a gas target. Subsequently the slow highly charged recoil ions are extracted from the ionization volume, and guided through a beam transport line to a Wien filter for charge state selection and to a collision region to study charge transfer processes. Several experiments were carried out to show the efficient charge state separation. Charge states up to q=15 were observed. When using a retarding field analyzer cross sections for single electron capture were determined for different charge states of Xe q+ for q=4 to 11 and He gas. The experiments demonstrated increasing charge transfer cross sections with increasing charge state q and indicated the effect of near resonant charge capture for q=6. The flexible data acquisition system used, is described and other future experiments, such as for instance in flight ion-trapping are indicated in the appendix. (orig.)

  12. VECTOR TOMOGRAPHY FOR THE CORONAL MAGNETIC FIELD. II. HANLE EFFECT MEASUREMENTS

    International Nuclear Information System (INIS)

    Kramar, M.; Inhester, B.; Lin, H.; Davila, J.

    2013-01-01

    In this paper, we investigate the feasibility of saturated coronal Hanle effect vector tomography or the application of vector tomographic inversion techniques to reconstruct the three-dimensional magnetic field configuration of the solar corona using linear polarization measurements of coronal emission lines. We applied Hanle effect vector tomographic inversion to artificial data produced from analytical coronal magnetic field models with equatorial and meridional currents and global coronal magnetic field models constructed by extrapolation of real photospheric magnetic field measurements. We tested tomographic inversion with only Stokes Q, U, electron density, and temperature inputs to simulate observations over large limb distances where the Stokes I parameters are difficult to obtain with ground-based coronagraphs. We synthesized the coronal linear polarization maps by inputting realistic noise appropriate for ground-based observations over a period of two weeks into the inversion algorithm. We found that our Hanle effect vector tomographic inversion can partially recover the coronal field with a poloidal field configuration, but that it is insensitive to a corona with a toroidal field. This result demonstrates that Hanle effect vector tomography is an effective tool for studying the solar corona and that it is complementary to Zeeman effect vector tomography for the reconstruction of the coronal magnetic field

  13. State of charge estimation for lithium-ion pouch batteries based on stress measurement

    International Nuclear Information System (INIS)

    Dai, Haifeng; Yu, Chenchen; Wei, Xuezhe; Sun, Zechang

    2017-01-01

    State of charge (SOC) estimation is one of the important tasks of battery management system (BMS). Being different from other researches, a novel method of SOC estimation for pouch lithium-ion battery cells based on stress measurement is proposed. With a comprehensive experimental study, we find that, the stress of the battery during charge/discharge is composed of the static stress and the dynamic stress. The static stress, which is the measured stress in equilibrium state, corresponds to SOC, this phenomenon facilitates the design of our stress-based SOC estimation. The dynamic stress, on the other hand, is influenced by multiple factors including charge accumulation or depletion, current and historical operation, thus a multiple regression model of the dynamic stress is established. Based on the relationship between static stress and SOC, as well as the dynamic stress modeling, the SOC estimation method is founded. Experimental results show that the stress-based method performs well with a good accuracy, and this method offers a novel perspective for SOC estimation. - Highlights: • A State of Charge estimator based on stress measurement is proposed. • The stress during charge and discharge is investigated with comprehensive experiments. • Effects of SOC, current, and operation history on battery stress are well studied. • A multiple regression model of the dynamic stress is established.

  14. How can we ensure that the coroner's autopsy is not an invasion of human rights?

    Science.gov (United States)

    Leadbeatter, Stephen; James, Ryk

    2018-01-01

    Despite public inquiries, and some changes to legislation following high-profile multiple homicides that were not detected by autopsy, coroners continue to rely largely on the autopsy. Regardless of the extent of quality failings and excess deaths at some hospitals, not detected through the coroner system, the autopsy is scarcely used by hospitals to monitor standards and educate. To explore when a compulsory medicolegal autopsy should, and should not, be used. Two hundred and thirty-six cases referred to a senior coroner were evaluated by pathologists with long experience of forensic, coronial and hospital autopsies, using detailed antecedent medical and circumstantial information: after their advice, the senior coroner decided what kind of autopsy provided sufficient information for his purposes. In nearly 40% (n=88) of deaths where the senior coroner accepted jurisdiction, issues raised could be resolved through analysis of medical records and antecedent information, supplemented only by detailed external examination of the body. Timely provision of sufficient information allows informed decisions about the requirement for, and nature and extent of, medical investigations into a death: unnecessary post mortem dissection is avoided, protecting the rights, under Articles 8 and 9 of the Human Rights Act 1998, of the bereaved to privacy, family life and religious practice. Although improvements in healthcare can undoubtedly result from detailed coroners' inquiries, those deaths where the matters investigated relate only to the accuracy of a natural cause of death or sit with a healthcare provider's internal quality assurance, should be investigated by the healthcare system in collaboration with the bereaved. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  15. Detecting charging state of ultra-fine particles: instrumental development and ambient measurements

    Directory of Open Access Journals (Sweden)

    L. Laakso

    2007-01-01

    Full Text Available The importance of ion-induced nucleation in the lower atmosphere has been discussed for a long time. In this article we describe a new instrumental setup – Ion-DMPS – which can be used to detect contribution of ion-induced nucleation on atmospheric new particle formation events. The device measures positively and negatively charged particles with and without a bipolar charger. The ratio between "charger off" to "charger on" describes the charging state of aerosol particle population with respect to equilibrium. Values above one represent more charges than in an equilibrium (overcharged state, and values below unity stand for undercharged situation, when there is less charges in the particles than in the equilibrium. We performed several laboratory experiments to test the operation of the instrument. After the laboratory tests, we used the device to observe particle size distributions during atmospheric new particle formation in a boreal forest. We found that some of the events were clearly dominated by neutral nucleation but in some cases also ion-induced nucleation contributed to the new particle formation. We also found that negative and positive ions (charged particles behaved in a different manner, days with negative overcharging were more frequent than days with positive overcharging.

  16. Reconstructed coronal views of CT and isotopic images of the pancreas

    International Nuclear Information System (INIS)

    Kasuga, Toshio; Kobayashi, Toshio; Nakanishi, Fumiko

    1980-01-01

    To compare functional images of the pancreas by scintigraphy with morphological views of the pancreas by CT, CT coronal views of the pancreas were reconstructed. As CT coronal views were reconstructed from the routine scanning, there was a problem in longitudinal spatial resolution. However, almost satisfactory total images of the pancreas were obtained by improving images adequately. In 27 patients whose diseases had been confirmed, it was easy to compare pancreatic scintigrams with pancreatic CT images by using reconstructed CT coronal views, and information which had not been obtained by original CT images could be obtained by using reconstructed CT coronal views. Especially, defects on pancreatic images and the shape of pancreas which had not been visualized clearly by scintigraphy alone could be visualized by using reconstructed CT coronal views of the pancreas. (Tsunoda, M.)

  17. Calculations on charge state and energy loss of argon ions in partially and fully ionized carbon plasmas.

    Science.gov (United States)

    Barriga-Carrasco, Manuel D; Casas, David; Morales, Roberto

    2016-03-01

    The energy loss of argon ions in a target depends on their velocity and charge density. At the energies studied in this work, it depends mostly on the free and bound electrons in the target. Here the random-phase approximation is used for analyzing free electrons at any degeneracy. For the plasma-bound electrons, an interpolation between approximations for low and high energies is applied. The Brandt-Kitagawa (BK) model is employed to depict the projectile charge space distribution, and the stripping criterion of Kreussler et al. is used to determine its equilibrium charge state Q(eq). This latter criterion implies that the equilibrium charge state depends slightly on the electron density and temperature of the plasma. On the other hand, the effective charge Q(eff) is obtained as the ratio between the energy loss of the argon ion and that of the proton for the same plasma conditions. This effective charge Q(eff) is larger than the equilibrium charge state Q(eq) due to the incorporation of the BK charge distribution. Though our charge-state estimations are not exactly the same as the experimental values, our energy loss agrees quite well with the experiments. It is noticed that the energy loss in plasmas is higher than that in the same cold target of about, ∼42-62.5% and increases with carbon plasma ionization. This confirms the well-known enhanced plasma stopping. It is also observed that only a small part of this energy loss enhancement is due to an increase of the argon charge state, namely only ∼2.2 and 5.1%, for the partially and the fully ionized plasma, respectively. The other contribution is connected with a better energy transfer to the free electrons at plasma state than to the bound electrons at solid state of about, ∼38.8-57.4%, where higher values correspond to a fully ionized carbon plasma.

  18. Cracking of charged polytropes with generalized polytropic equation of state

    Energy Technology Data Exchange (ETDEWEB)

    Azam, M. [University of Education, Division of Science and Technology, Lahore (Pakistan); Mardan, S.A. [University of the Management and Technology, Department of Mathematics, Lahore (Pakistan)

    2017-02-15

    We discuss the occurrence of cracking in charged anisotropic polytropes with generalized polytropic equation of state through two different assumptions; (i) by carrying out local density perturbations under a conformally flat condition (ii) by perturbing anisotropy, polytropic index and charge parameters. For this purpose, we consider two different definitions of polytropes that exist in literature. We conclude that under local density perturbations scheme cracking does not appear in both types of polytropes and stable configuration is observed, while with the second type of perturbation cracking appears in both types of polytropes under certain conditions. (orig.)

  19. Characteristics of Low-latitude Coronal Holes near the Maximum of Solar Cycle 24

    Energy Technology Data Exchange (ETDEWEB)

    Hofmeister, Stefan J.; Veronig, Astrid; Reiss, Martin A.; Temmer, Manuela [University of Graz, Institute of Physics, IGAM-Kanzelhöhe Observatory, Graz (Austria); Vennerstrom, Susanne [National Space Institute, DTU Space (Denmark); Vršnak, Bojan [Hvar Observatory, Faculty of Geodesy, Zagreb (Croatia); Heber, Bernd, E-mail: stefan.hofmeister@uni-graz.at [Universität Kiel, Institut für Experimentelle und Angewandte Physik, Kiel (Germany)

    2017-02-01

    We investigate the statistics of 288 low-latitude coronal holes extracted from SDO /AIA-193 filtergrams over the time range of 2011 January 01–2013 December 31. We analyze the distribution of characteristic coronal hole properties, such as the areas, mean AIA-193 intensities, and mean magnetic field densities, the local distribution of the SDO /AIA-193 intensity and the magnetic field within the coronal holes, and the distribution of magnetic flux tubes in coronal holes. We find that the mean magnetic field density of all coronal holes under study is 3.0 ± 1.6 G, and the percentaged unbalanced magnetic flux is 49 ± 16%. The mean magnetic field density, the mean unsigned magnetic field density, and the percentaged unbalanced magnetic flux of coronal holes depend strongly pairwise on each other, with correlation coefficients cc > 0.92. Furthermore, we find that the unbalanced magnetic flux of the coronal holes is predominantly concentrated in magnetic flux tubes: 38% (81%) of the unbalanced magnetic flux of coronal holes arises from only 1% (10%) of the coronal hole area, clustered in magnetic flux tubes with field strengths >50 G (10 G). The average magnetic field density and the unbalanced magnetic flux derived from the magnetic flux tubes correlate with the mean magnetic field density and the unbalanced magnetic flux of the overall coronal hole (cc>0.93). These findings give evidence that the overall magnetic characteristics of coronal holes are governed by the characteristics of the magnetic flux tubes.

  20. To the problem on a charge state of energetic ions of radiation belts

    International Nuclear Information System (INIS)

    Panasyuk, M.I.

    1980-01-01

    Estimation of the effect of recharging processes upon formation of intensity maxima of radiation belt ions of different types is obtained as well as the ion charge states in the area of intensity maxima. Comparison of spatial position of intensity maxima of the H, He, C, O ions with the energies more than 1 MeV with the calculation results is presented. It provides the particle radial drift under the effect of sudden impulses and death at the expence of ionization losses. Application of adiabaticity criterion of the particle movement to the analysis of position of outer edge of radiation belt of heavy ions permitted to carry out estimation of the He, C, O ion charge state. He ions with the energy more than 1 MeV possess mainly the charge state of +2, C and O ions with the energy of several MeV over L=5-6 are in the ionized state almost completely, and during the drift into the depth of the belts the ion charge decreases to 3-4 over L approximately 3.5 with the energy increase. At the energies higher than several MeV the recharge processes are significant for the C and.O ions. For He ions with the energy higher 1 MeV and for H ions with more than 0.1 MeV the recharge role is not considerable

  1. High Charge State Ions Extracted from Metal Plasmas in the Transition Regime from Vacuum Spark to High Current Vacuum Arc

    International Nuclear Information System (INIS)

    Yushkov, Georgy Yu.; Anders, A.

    2008-01-01

    Metal ions were extracted from pulsed discharge plasmas operating in the transition region between vacuum spark (transient high voltage of kV) and vacuum arc (arc voltage ∼ 20 V). At a peak current of about 4 kA, and with a pulse duration of 8 (micro)s, we observed mean ion charges states of about 6 for several cathode materials. In the case of platinum, the highest average charge state was 6.74 with ions of charge states as high as 10 present. For gold we found traces of charge state 11, with the highest average charge state of 7.25. At currents higher than 5 kA, non-metallic contaminations started to dominate the ion beam, preventing further enhancement of the metal charge states

  2. Ion charge-state production and photoionization near the K edge in argon and potassium

    International Nuclear Information System (INIS)

    Berry, H.G.; Azuma, Y.; Cowan, P.L.; Gemmell, D.S.; LeBrun, T.; Amusia, M.Y.

    1994-01-01

    We have measured the time-of-flight charge distributions of ions of argon and potassium following x-ray absorption at energies near their respective K edges. We confirm previously observed enhancements of the higher charge states at energies up to 100 eV below the K edge in argon. The measurements confirm recent calculations suggesting excitation of a virtual 1s state in this energy range

  3. Plasma Diagnostics of Coronal Dimming Events

    Science.gov (United States)

    Vanninathan, Kamalam; Veronig, Astrid M.; Dissauer, Karin; Temmer, Manuela

    2018-04-01

    Coronal mass ejections are often associated with coronal dimmings, i.e., transient dark regions that are most distinctly observed in Extreme Ultra-violet wavelengths. Using Atmospheric Imaging Assembly (AIA) data, we apply Differential Emission Measure diagnostics to study the plasma characteristics of six coronal dimming events. In the core dimming region, we find a steep and impulsive decrease of density with values up to 50%–70%. Five of the events also reveal an associated drop in temperature of 5%–25%. The secondary dimming regions also show a distinct decrease in density, but less strong, decreasing by 10%–45%. In both the core and the secondary dimming the density changes are much larger than the temperature changes, confirming that the dimming regions are mainly caused by plasma evacuation. In the core dimming, the plasma density reduces rapidly within the first 20–30 minutes after the flare start and does not recover for at least 10 hr later, whereas the secondary dimming tends to be more gradual and starts to replenish after 1–2 hr. The pre-event temperatures are higher in the core dimming (1.7–2.6 MK) than in the secondary dimming regions (1.6–2.0 MK). Both core and secondary dimmings are best observed in the AIA 211 and 193 Å filters. These findings suggest that the core dimming corresponds to the footpoints of the erupting flux rope rooted in the AR, while the secondary dimming represents plasma from overlying coronal structures that expand during the CME eruption.

  4. Coronal holes and high-speed wind streams

    International Nuclear Information System (INIS)

    Zirker, J.B.

    1977-01-01

    Coronal holes low have been identified as Bartel's M regions, i.e., sources of high-speed wind streams that produce recurrent geomagnetic variations. Throughout the Skylab period the polar caps of the Sun were coronal holes, and at lower latitudes the most persistent and recurrent holes were equatorial extensions of the polar caps. The holes rotated 'rigidly' at the equatorial synodic rate. They formed in regions of unipolar photospheric magnetic field, and their internal magnetic fields diverged rapidly with increasing distance from the sun. The geometry of the magnetic field in the inner corona seems to control both the physical properties of the holes and the global distribution of high-speed wind streams in the heliosphere. The latitude variation of the divergence of the coronal magnetic field lines produces corresponding variations in wind speed.During the years of declining solar activity the global field of the corona approximates a perturbed dipole. The divergence of field lines in each hemisphere produces a high-speed wind near the poles and low-speed wind in a narrow belt that coincides with the magnetic neutral sheet. The analysis of electron density measurements within a polar hole indicates that solar wind is accelerated principally in the region between 2 and 5 R/sub s/ and that mechanical wave pressure (possibly Alfven wave) may be responsible for the accleration of the wind. Phenomenological models for the birth and decay of coronal holes have been proposed. Attempts to explain the birth and rigid rotation of holes through dynamo action have been only partially successful. The 11-year variation of cosmic ray intensities at the earth may result from cyclic variation of open field regions associated with coronal holes

  5. Observations and Numerical Models of Solar Coronal Heating Associated with Spicules

    Energy Technology Data Exchange (ETDEWEB)

    Pontieu, B. De; Martinez-Sykora, J. [Lockheed Martin Solar and Astrophysics Laboratory, 3251 Hanover Street, Org. A021S, Building 252, Palo Alto, CA 94304 (United States); Moortel, I. De [School of Mathematics and Statistics, University of St Andrews, St Andrews, Fife KY16 9SS (United Kingdom); McIntosh, S. W. [High Altitude Observatory, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307 (United States)

    2017-08-20

    Spicules have been proposed as significant contributors to the mass and energy balance of the corona. While previous observations have provided a glimpse of short-lived transient brightenings in the corona that are associated with spicules, these observations have been contested and are the subject of a vigorous debate both on the modeling and the observational side. Therefore, it remains unclear whether plasma is heated to coronal temperatures in association with spicules. We use high-resolution observations of the chromosphere and transition region (TR) with the Interface Region Imaging Spectrograph and of the corona with the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory to show evidence of the formation of coronal structures associated with spicular mass ejections and heating of plasma to TR and coronal temperatures. Our observations suggest that a significant fraction of the highly dynamic loop fan environment associated with plage regions may be the result of the formation of such new coronal strands, a process that previously had been interpreted as the propagation of transient propagating coronal disturbances. Our observations are supported by 2.5D radiative MHD simulations that show heating to coronal temperatures in association with spicules. Our results suggest that heating and strong flows play an important role in maintaining the substructure of loop fans, in addition to the waves that permeate this low coronal environment.

  6. Theoretical Study of the Charge-Transfer State Separation within Marcus Theory: The C60-Anthracene Case Study.

    Science.gov (United States)

    Volpi, Riccardo; Nassau, Racine; Nørby, Morten Steen; Linares, Mathieu

    2016-09-21

    We study, within Marcus theory, the possibility of the charge-transfer (CT) state splitting at organic interfaces and a subsequent transport of the free charge carriers to the electrodes. As a case study we analyze model anthracene-C60 interfaces. Kinetic Monte Carlo (KMC) simulations on the cold CT state were performed at a range of applied electric fields, and with the fields applied at a range of angles to the interface to simulate the action of the electric field in a bulk heterojunction (BHJ) interface. The results show that the inclusion of polarization in our model increases CT state dissociation and charge collection. The effect of the electric field on CT state splitting and free charge carrier conduction is analyzed in detail with and without polarization. Also, depending on the relative orientation of the anthracene and C60 molecules at the interface, CT state splitting shows different behavior with respect to both applied field strength and applied field angle. The importance of the hot CT in helping the charge carrier dissociation is also analyzed in our scheme.

  7. Gap states of charged soliton in polyacetylene

    International Nuclear Information System (INIS)

    Lu Dingwei; Liu Jie; Fu Rouli

    1988-10-01

    By considering the electron interaction in polyacetylene, it is found that two gap states in charged solitons of trans-polyacetylene exist: one is deep level, another is shallow level. The deep one shifts 0.23 ev down (for positive soliton) or up (for negative soliton) from the center of the gap; while the shallow one is 0.06 ev under the bottom of conduction band (positive soliton) or above the top of valence band (negative soliton). These results agree with the absorption spectra of trans-polyacetylene. (author). 5 refs, 4 figs

  8. Equilibrium and non-equilibrium charge-state distributions of 2.0 MeV/u carbon ions passing through carbon foils

    International Nuclear Information System (INIS)

    Imai, M.; Sataka, M.; Matsuda, M.; Okayasu, S.; Kawatsura, K.; Takahiro, K.; Komaki, K.; Shibata, H.; Nishio, K.

    2015-01-01

    Both equilibrium and non-equilibrium charge-state distributions were studied experimentally for 2.0 MeV/u carbon ions after passing through carbon foils. Measured charge-state distribution established the equilibrium at a target thickness of 10 μg/cm 2 and this remained unchanged until a maximum target thickness of 98 μg/cm 2 . The equilibrium charge-state distribution, the equilibrium mean charge-state, and the width and skewness of the equilibrium distribution were compared with predictions using existing semi-empirical formulae as well as simulation results, including the ETACHA code. It was found that charge-state distributions, mean charge states, and distribution widths for C 2+ , C 3+ , and C 4+ incident ions merged into quasi-equilibrium values at a target thickness of 5.7 μg/cm 2 in the pre-equilibrium region and evolved simultaneously to the ‘real equilibrium’ values for all of the initial charge states, including C 5+ and C 6+ ions, as previously demonstrated for sulfur projectile ions at the same velocity (Imai et al., 2009). Two kinds of simulation, ETACHA and solution of rate equations taking only single electron transfers into account, were used, and both of them reproduced the measured charge evolution qualitatively. The quasi-equilibrium behavior could be reproduced with the ETACHA code, but not with solution of elementary rate equations

  9. A study of charge state approach to the stopping power of MeV B, N, and O ions in carbon

    International Nuclear Information System (INIS)

    Li, M.M.; O'Connor, D.J.; Timmers, H.; Dastoor, P.C.

    1999-01-01

    The charge state approach has been applied to treat the electronic stopping powers of swift O, N and B ions in carbon foil. According to the charge state model, the contributions to the electronic stopping power of energetic projectiles passing through solid targets are due to collisional interactions and from the charge exchange process. The definition of fractional effective charge from Brandt and Kitagawa has been combined into the current charge state model. Extensive applications of this approach require data of the equilibrium charge state distributions and knowledge of charge-exchange cross sections-involving electronic capture and loss processes. Both measured data and empirical calculations of the equilibrium charge state fraction are used in the study, and the electronic capture cross sections are obtained with the eikonal Brinkman-Kramers approximation (EBK). By comparing the numerical results with the latest experimental data as well as empirical values, it is shown that the present approach slightly overestimates the energy loss at the intermediate velocity region

  10. Charge transfer excitations from excited state Hartree-Fock subsequent minimization scheme

    International Nuclear Information System (INIS)

    Theophilou, Iris; Tassi, M.; Thanos, S.

    2014-01-01

    Photoinduced charge-transfer processes play a key role for novel photovoltaic phenomena and devices. Thus, the development of ab initio methods that allow for an accurate and computationally inexpensive treatment of charge-transfer excitations is a topic that nowadays attracts a lot of scientific attention. In this paper we extend an approach recently introduced for the description of single and double excitations [M. Tassi, I. Theophilou, and S. Thanos, Int. J. Quantum Chem. 113, 690 (2013); M. Tassi, I. Theophilou, and S. Thanos, J. Chem. Phys. 138, 124107 (2013)] to allow for the description of intermolecular charge-transfer excitations. We describe an excitation where an electron is transferred from a donor system to an acceptor one, keeping the excited state orthogonal to the ground state and avoiding variational collapse. These conditions are achieved by decomposing the space spanned by the Hartree-Fock (HF) ground state orbitals into four subspaces: The subspace spanned by the occupied orbitals that are localized in the region of the donor molecule, the corresponding for the acceptor ones and two more subspaces containing the virtual orbitals that are localized in the neighborhood of the donor and the acceptor, respectively. Next, we create a Slater determinant with a hole in the subspace of occupied orbitals of the donor and a particle in the virtual subspace of the acceptor. Subsequently we optimize both the hole and the particle by minimizing the HF energy functional in the corresponding subspaces. Finally, we test our approach by calculating the lowest charge-transfer excitation energies for a set of tetracyanoethylene-hydrocarbon complexes that have been used earlier as a test set for such kind of excitations

  11. Excited State Structural Dynamics of Carotenoids and Charge Transfer Systems

    International Nuclear Information System (INIS)

    Van Tassle, Aaron Justin

    2006-01-01

    This dissertation describes the development and implementation of a visible/near infrared pump/mid-infrared probe apparatus. Chapter 1 describes the background and motivation of investigating optically induced structural dynamics, paying specific attention to solvation and the excitation selection rules of highly symmetric molecules such as carotenoids. Chapter 2 describes the development and construction of the experimental apparatus used throughout the remainder of this dissertation. Chapter 3 will discuss the investigation of DCM, a laser dye with a fluorescence signal resulting from a charge transfer state. By studying the dynamics of DCM and of its methyl deuterated isotopomer (an otherwise identical molecule), we are able to investigate the origins of the charge transfer state and provide evidence that it is of the controversial twisted intramolecular (TICT) type. Chapter 4 introduces the use of two-photon excitation to the S1 state, combined with one-photon excitation to the S2 state of the carotenoid beta-apo-8'-carotenal. These 2 investigations show evidence for the formation of solitons, previously unobserved in molecular systems and found only in conducting polymers Chapter 5 presents an investigation of the excited state dynamics of peridinin, the carotenoid responsible for the light harvesting of dinoflagellates. This investigation allows for a more detailed understanding of the importance of structural dynamics of carotenoids in light harvesting

  12. Are interplanetary magnetic clouds manifestations of coronal transients at 1 AU

    International Nuclear Information System (INIS)

    Wilson, R.M.; Hildner, E.

    1984-01-01

    Using proxy data for the occurrence of those mass ejections from the solar corona which are directed earthward, we investigate the association between the post-1970 interplanetary magnetic clouds of Klein and Burlaga (1982) and coronal mass ejections. The evidence linking magnetic clouds following shocks with coronal mass ejections is striking; six of nine clouds observed at Earth were preceded an appropriate time earlier by meter-wave type II radio bursts indicative of coronal shock waves and coronal mass ejections occurring near central meridian. During the selected control periods when no clouds were detected near Earth, the only type II bursts reported were associated with solar activity near the limbs. Where the proxy solar data to be sought are not so clearly suggested, that is, for clouds preceding interaction regions and clouds within cold magnetic enhancements, the evidence linking the clouds and coronal mass ejections is not as clear; proxy data usually suggest many candidate mass-ejection events for each cloud. Overall, the data are consistent with and support the hypothesis suggested by Klein and Burlaga that magnetic clouds observed with spacecraft at 1 AU are manifestations of solar coronal mass ejection transients. (orig.)

  13. An intramolecular charge transfer state of carbonyl carotenoids: implications for excited state dynamics of apo-carotenals and retinal

    Czech Academy of Sciences Publication Activity Database

    Polívka, Tomáš; Kaligotla, S.; Chábera, P.; Frank, H.A.

    2011-01-01

    Roč. 13, č. 22 (2011), s. 1463-9076 ISSN 1463-9076 Institutional research plan: CEZ:AV0Z50510513 Keywords : carotenoid * retinal * excited-state dynamics * charge-transfer state Subject RIV: BO - Biophysics Impact factor: 3.573, year: 2011

  14. Calcium K-line network in coronal holes

    Energy Technology Data Exchange (ETDEWEB)

    Marsh, K A [Hale Observatories, Pasadena, Calif. (USA)

    1977-05-01

    Microphotometry of calcium K-line photographs in the regions of polar coronal holes shows that the chromospheric network exterior to a hole has a slightly broader intensity distribution than that inside the hole itself, a fact which can be attributed to a greater number of bright network elements outside the hole. These bright elements presumably represent the enhanced network resulting from the dispersal of magnetic flux from old active regions, a hypothesis which is consistent with current ideas of coronal hole formation.

  15. Polarization of Coronal Forbidden Lines

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hao; Qu, Zhongquan [Yunnan Observatories, Chinese Academy of Sciences, Kunming, Yunnan 650011 (China); Landi Degl’Innocenti, Egidio, E-mail: sayahoro@ynao.ac.cn [Dipartimento di Astronomia e Scienza dello Spazio, Università di Firenze, Largo E. Fermi 2, I-50125 Firenze (Italy)

    2017-03-20

    Since the magnetic field is responsible for most manifestations of solar activity, one of the most challenging problems in solar physics is the diagnostics of solar magnetic fields, particularly in the outer atmosphere. To this end, it is important to develop rigorous diagnostic tools to interpret polarimetric observations in suitable spectral lines. This paper is devoted to analyzing the diagnostic content of linear polarization imaging observations in coronal forbidden lines. Although this technique is restricted to off-limb observations, it represents a significant tool to diagnose the magnetic field structure in the solar corona, where the magnetic field is intrinsically weak and still poorly known. We adopt the quantum theory of polarized line formation developed in the framework of the density matrix formalism, and synthesize images of the emergent linear polarization signal in coronal forbidden lines using potential-field source-surface magnetic field models. The influence of electronic collisions, active regions, and Thomson scattering on the linear polarization of coronal forbidden lines is also examined. It is found that active regions and Thomson scattering are capable of conspicuously influencing the orientation of the linear polarization. These effects have to be carefully taken into account to increase the accuracy of the field diagnostics. We also found that linear polarization observation in suitable lines can give valuable information on the long-term evolution of the magnetic field in the solar corona.

  16. Temperature Structure of a Coronal Cavity

    Science.gov (United States)

    Kucera, T. A.; Gibson, S. E.; Schmit, D. J.

    2011-01-01

    we analyze the temperature structure of a coronal cavity observed in Aug. 2007. coronal cavities are long, low-density structures located over filament neutral lines and are often seen as dark elliptical features at the solar limb in white light, EUV and x-rays. when these structures erupt they form the cavity portions of CMEs. It is important to establish the temperature structure of cavities in order to understand the thermodynamics of cavities in relation to their three-dimensional magnetic structure. To analyze the temperature we compare temperature ratios of a series of iron lines observed by the Hinode/EUv Imaging spectrometer (EIS). We also use those lines to constrain a forward model of the emission from the cavity and streamer. The model assumes a coronal streamer with a tunnel-like cavity with elliptical cross-section and a Gaussian variation of height along the tunnel lenth. Temperature and density can be varied as a function of altitude both in the cavity and streamer. The general cavity morphology and the cavity and streamer density have already been modeled using data from STEREO's SECCHI/EUVI and Hinode/EIS (Gibson et al 2010 and Schmit & Gibson 2011).

  17. Aerosol charging state at an urban site: new analytical approach and implications for ion-induced nucleation

    Directory of Open Access Journals (Sweden)

    S. Gagné

    2012-05-01

    Full Text Available The charging state of aerosol populations was determined using an Ion-DMPS in Helsinki, Finland between December 2008 and February 2010. We extrapolated the charging state and calculated the ion-induced nucleation fraction to be around 1.3 % ± 0.4 % at 2 nm and 1.3 % ± 0.5 % at 1.5 nm, on average. We present a new method to retrieve the average charging state for a new particle formation event, at a given size and polarity. We improve the uncertainty assessment and fitting technique used previously with an Ion-DMPS. We also use a new theoretical framework that allows for different concentrations of small ions for different polarities (polarity asymmetry. We extrapolate the ion-induced fraction using polarity symmetry and asymmetry. Finally, a method to calculate the growth rates from the behaviour of the charging state as a function of the particle diameter using polarity symmetry and asymmetry is presented and used on a selection of new particle formation events.

  18. Multi-charge-state molecular dynamics and self-diffusion coefficient in the warm dense matter regime

    Science.gov (United States)

    Fu, Yongsheng; Hou, Yong; Kang, Dongdong; Gao, Cheng; Jin, Fengtao; Yuan, Jianmin

    2018-01-01

    We present a multi-ion molecular dynamics (MIMD) simulation and apply it to calculating the self-diffusion coefficients of ions with different charge-states in the warm dense matter (WDM) regime. First, the method is used for the self-consistent calculation of electron structures of different charge-state ions in the ion sphere, with the ion-sphere radii being determined by the plasma density and the ion charges. The ionic fraction is then obtained by solving the Saha equation, taking account of interactions among different charge-state ions in the system, and ion-ion pair potentials are computed using the modified Gordon-Kim method in the framework of temperature-dependent density functional theory on the basis of the electron structures. Finally, MIMD is used to calculate ionic self-diffusion coefficients from the velocity correlation function according to the Green-Kubo relation. A comparison with the results of the average-atom model shows that different statistical processes will influence the ionic diffusion coefficient in the WDM regime.

  19. Exploration of charge states of balanol analogues acting as ATP-competitive inhibitors in kinases.

    Science.gov (United States)

    Hardianto, Ari; Yusuf, Muhammad; Liu, Fei; Ranganathan, Shoba

    2017-12-28

    (-)-Balanol is an ATP mimic that inhibits protein kinase C (PKC) isozymes and cAMP-dependent protein kinase (PKA) with limited selectivity. While PKA is a tumour promoter, PKC isozymes act as tumour promoters or suppressors, depending on the cancer type. In particular, PKCε is frequently implicated in cancer promotion, making it a potential target for anticancer drugs. To improve isozyme selectivity of balanol, exhaustive structural and activity relationship (SAR) studies have been performed in the last two decades, but with limited success. More recently, fluorination on balanol has shown improved selectivity for PKCε, although the fluorine effect is not yet clearly understood. Understanding the origin to this fluorine-based selectivity will be valuable for designing better balanol-based ATP mimicking inhibitors. Computational approaches such as molecular dynamics (MD) simulations can decipher the fluorine effect, provided that correct charges have been assigned to a ligand. Balanol analogues have multiple ionisable functional groups and the effect of fluorine substitutions on the exact charge state of each analogue bound to PKA and to PKCε needs to be thoroughly investigated in order to design highly selective inhibitors for therapeutic applications. We explored the charge states of novel fluorinated balanol analogues using MD simulations. For different potential charge states of these analogues, Molecular Mechanics Generalized Born Surface Area (MMGBSA) binding energy values were computed. This study suggests that balanol and the most potent fluorinated analogue (5S fluorine substitution on the azepane ring), have charges on the azepane ring (N1), and the phenolic (C6''OH) and the carboxylate (C15''O 2 H) groups on the benzophenone moiety, when bound to PKCε as well as PKA. To the best our knowledge, this is the first study showing that the phenolate group is charged in balanol and its analogues binding to the ATP site of PKCε. Correct charge

  20. Coherent and Semiclassical States of a Charged Particle in Electromagnetic Fields

    Science.gov (United States)

    Pereira, A. S.

    2018-03-01

    In the present article, we extend our study (Bagrov et al., Braz. J. Phys. 45, 369, 2015) of generalized coherent states (GCS) of a one-dimensional particle considering such important physical system as a three-dimensional charged particle in electric and magnetic fields. Constructing GCS in a many-dimensional case, we meet technical complications that make the consideration nontrivial and instructive. The GCS of the system under consideration are constructed. We study the properties of this GCS such as completeness relations, minimization of uncertainty relations, and so on. We point out which family of the obtained GCS of a charged particle in a magnetic field is related to the CS constructed first by Malkin and Man'ko. We obtain conditions under which some of the GCS can be considered as semiclassical states (SS).

  1. Coherent and Semiclassical States of a Charged Particle in Electromagnetic Fields

    Science.gov (United States)

    Pereira, A. S.

    2018-06-01

    In the present article, we extend our study (Bagrov et al., Braz. J. Phys. 45, 369, 2015) of generalized coherent states (GCS) of a one-dimensional particle considering such important physical system as a three-dimensional charged particle in electric and magnetic fields. Constructing GCS in a many-dimensional case, we meet technical complications that make the consideration nontrivial and instructive. The GCS of the system under consideration are constructed. We study the properties of this GCS such as completeness relations, minimization of uncertainty relations, and so on. We point out which family of the obtained GCS of a charged particle in a magnetic field is related to the CS constructed first by Malkin and Man'ko. We obtain conditions under which some of the GCS can be considered as semiclassical states (SS).

  2. Hybrid fuzzy charged system search algorithm based state estimation in distribution networks

    Directory of Open Access Journals (Sweden)

    Sachidananda Prasad

    2017-06-01

    Full Text Available This paper proposes a new hybrid charged system search (CSS algorithm based state estimation in radial distribution networks in fuzzy framework. The objective of the optimization problem is to minimize the weighted square of the difference between the measured and the estimated quantity. The proposed method of state estimation considers bus voltage magnitude and phase angle as state variable along with some equality and inequality constraints for state estimation in distribution networks. A rule based fuzzy inference system has been designed to control the parameters of the CSS algorithm to achieve better balance between the exploration and exploitation capability of the algorithm. The efficiency of the proposed fuzzy adaptive charged system search (FACSS algorithm has been tested on standard IEEE 33-bus system and Indian 85-bus practical radial distribution system. The obtained results have been compared with the conventional CSS algorithm, weighted least square (WLS algorithm and particle swarm optimization (PSO for feasibility of the algorithm.

  3. 3D Global Coronal Density Structure and Associated Magnetic Field near Solar Maximum

    Energy Technology Data Exchange (ETDEWEB)

    Kramar, Maxim [Physics Department, The Catholic University of America, Washington, DC (United States); Airapetian, Vladimir [Department of Physics and Astronomy, George Mason University, Fairfax, VA (United States); NASA/Goddard Space Flight Center, Code 671, Greenbelt, MD (United States); Lin, Haosheng, E-mail: vladimir.airapetian@nasa.gov [College of Natural Sciences, Institute for Astronomy, University of Hawaii at Manoa, Pukalani, HI (United States)

    2016-08-09

    Measurement of the coronal magnetic field is a crucial ingredient in understanding the nature of solar coronal dynamic phenomena at all scales. We employ STEREO/COR1 data obtained near maximum of solar activity in December 2012 (Carrington rotation, CR 2131) to retrieve and analyze the three-dimensional (3D) coronal electron density in the range of heights from 1.5 to 4 R{sub ⊙} using a tomography method and qualitatively deduce structures of the coronal magnetic field. The 3D electron density analysis is complemented by the 3D STEREO/EUVI emissivity in 195 Å band obtained by tomography for the same CR period. We find that the magnetic field configuration during CR 2131 has a tendency to become radially open at heliocentric distances below ~2.5 R{sub ⊙}. We compared the reconstructed 3D coronal structures over the CR near the solar maximum to the one at deep solar minimum. Results of our 3D density reconstruction will help to constrain solar coronal field models and test the accuracy of the magnetic field approximations for coronal modeling.

  4. 3D Global Coronal Density Structure and Associated Magnetic Field near Solar Maximum

    Directory of Open Access Journals (Sweden)

    Maxim Kramar

    2016-08-01

    Full Text Available Measurement of the coronal magnetic field is a crucial ingredient in understanding the nature of solar coronal dynamic phenomena at all scales. We employ STEREO/COR1 data obtained near maximum of solar activity in December 2012 (Carrington rotation, CR 2131 to retrieve and analyze the three-dimensional (3D coronal electron density in the range of heights from $1.5$ to $4 R_odot$ using a tomography method and qualitatively deduce structures of the coronal magnetic field. The 3D electron density analysis is complemented by the 3D STEREO/EUVI emissivity in 195 AA band obtained by tomography for the same CR period. We find that the magnetic field configuration during CR 2131 has a tendency to become radially open at heliocentric distances below $sim 2.5 R_odot$. We compared the reconstructed 3D coronal structures over the CR near the solar maximum to the one at deep solar minimum. Results of our 3D density reconstruction will help to constrain solar coronal field models and test the accuracy of the magnetic field approximations for coronal modeling.

  5. 42 CFR 489.34 - Allowable charges: Hospitals participating in State reimbursement control systems or...

    Science.gov (United States)

    2010-10-01

    ... reimbursement control systems or demonstration projects. 489.34 Section 489.34 Public Health CENTERS FOR... CERTIFICATION PROVIDER AGREEMENTS AND SUPPLIER APPROVAL Allowable Charges § 489.34 Allowable charges: Hospitals participating in State reimbursement control systems or demonstration projects. A hospital receiving payment for...

  6. Smart and accurate state-of-charge indication in portable applications

    NARCIS (Netherlands)

    Pop, V.; Bergveld, H.J.; Notten, P.H.L.; Regtien, P.P.L.

    2005-01-01

    Accurate state-of-charge (SoC) and remaining run-time indication for portable devices is important for the user-convenience and to prolong the lifetime of batteries. However, the known methods of SoC indication in portable applications are not accurate enough under all practical conditions. The

  7. Smart and accurate State-of-Charge indication in Portable Applications

    NARCIS (Netherlands)

    Pop, V.; Bergveld, H.J.; Notten, P.H.L.; Regtien, Paulus P.L.

    2006-01-01

    Accurate state-of-charge (SoC) and remaining run-time indication for portable devices is important for the user-convenience and to prolong the lifetime of batteries. However, the known methods of SoC indication in portable applications are not accurate enough under all practical conditions. The

  8. Observation of excited state charge transfer with fs/ps-CARS

    International Nuclear Information System (INIS)

    Blom, Alex Jason

    2009-01-01

    Excited state charge transfer processes are studied using the fs/ps-CARS probe technique. This probe allows for multiplexed detection of Raman active vibrational modes. Systems studied include Michler's Ketone, Coumarin 120, 4-dimethylamino-4(prime)-nitrostilbene, and several others. The vibrational spectrum of the para di-substituted benzophenone Michler's Ketone in the first excited singlet state is studied for the first time. It is found that there are several vibrational modes indicative of structural changes of the excited molecule. A combined experimental and theoretical approach is used to study the simplest 7-amino-4-methylcoumarin, Coumarin 120. Vibrations observed in FTIR and spontaneous Raman spectra are assigned using density functional calculations and a continuum solvation model is used to predict how observed modes are affected upon inclusion of a solvent. The low frequency modes of the excited state charge transfer species 4-dimethylamino-4(prime)-nitrostilbene are studied in acetonitrile. Results are compared to previous work on this molecule in the fingerprint region. Finally, several partially completed projects and their implications are discussed. These include the two photon absorption of Coumarin 120, nanoconfinement in cyclodextrin cavities and sensitization of titania nanoparticles

  9. Observation of excited state charge transfer with fs/ps-CARS

    Energy Technology Data Exchange (ETDEWEB)

    Blom, Alex Jason [Iowa State Univ., Ames, IA (United States)

    2009-01-01

    Excited state charge transfer processes are studied using the fs/ps-CARS probe technique. This probe allows for multiplexed detection of Raman active vibrational modes. Systems studied include Michler's Ketone, Coumarin 120, 4-dimethylamino-4'-nitrostilbene, and several others. The vibrational spectrum of the para di-substituted benzophenone Michler's Ketone in the first excited singlet state is studied for the first time. It is found that there are several vibrational modes indicative of structural changes of the excited molecule. A combined experimental and theoretical approach is used to study the simplest 7-amino-4-methylcoumarin, Coumarin 120. Vibrations observed in FTIR and spontaneous Raman spectra are assigned using density functional calculations and a continuum solvation model is used to predict how observed modes are affected upon inclusion of a solvent. The low frequency modes of the excited state charge transfer species 4-dimethylamino-4{prime}-nitrostilbene are studied in acetonitrile. Results are compared to previous work on this molecule in the fingerprint region. Finally, several partially completed projects and their implications are discussed. These include the two photon absorption of Coumarin 120, nanoconfinement in cyclodextrin cavities and sensitization of titania nanoparticles.

  10. Proton-coupled electron transfer versus hydrogen atom transfer: generation of charge-localized diabatic states.

    Science.gov (United States)

    Sirjoosingh, Andrew; Hammes-Schiffer, Sharon

    2011-03-24

    The distinction between proton-coupled electron transfer (PCET) and hydrogen atom transfer (HAT) mechanisms is important for the characterization of many chemical and biological processes. PCET and HAT mechanisms can be differentiated in terms of electronically nonadiabatic and adiabatic proton transfer, respectively. In this paper, quantitative diagnostics to evaluate the degree of electron-proton nonadiabaticity are presented. Moreover, the connection between the degree of electron-proton nonadiabaticity and the physical characteristics distinguishing PCET from HAT, namely, the extent of electronic charge redistribution, is clarified. In addition, a rigorous diabatization scheme for transforming the adiabatic electronic states into charge-localized diabatic states for PCET reactions is presented. These diabatic states are constructed to ensure that the first-order nonadiabatic couplings with respect to the one-dimensional transferring hydrogen coordinate vanish exactly. Application of these approaches to the phenoxyl-phenol and benzyl-toluene systems characterizes the former as PCET and the latter as HAT. The diabatic states generated for the phenoxyl-phenol system possess physically meaningful, localized electronic charge distributions that are relatively invariant along the hydrogen coordinate. These diabatic electronic states can be combined with the associated proton vibrational states to generate the reactant and product electron-proton vibronic states that form the basis of nonadiabatic PCET theories. Furthermore, these vibronic states and the corresponding vibronic couplings may be used to calculate rate constants and kinetic isotope effects of PCET reactions.

  11. Self/anti-self charge conjugate states in the helicity basis

    International Nuclear Information System (INIS)

    Dvoeglazov, Valeriy V.

    2013-01-01

    We construct self/anti-self charge conjugate (Majorana-like) states for the (1/2,0)⊕(0,1/2) representation of the Lorentz group, and their analogs for higher spins within the quantum field theory. The problem of the basis rotations and that of the selection of phases in the Dirac-like and Majorana-like field operators are considered. The discrete symmetries properties (P, C, T) are studied. Particular attention has been paid to the question of (anti)commutation of the Charge conjugation operator and the Parity in the helicity basis. Dynamical equations have also been presented. In the (1/2,0)⊕(0,1/2) representation they obey the Dirac-like equation with eight components, which has been first introduced by Markov. Thus, the Fock space for corresponding quantum fields is doubled (as shown by Ziino). The chirality and the helicity (two concepts which are frequently confused in the literature) for Dirac and Majorana states have been discussed

  12. Mid-term periodicities and heliospheric modulation of coronal index ...

    Indian Academy of Sciences (India)

    PRITHVI RAJ SINGH

    2018-03-06

    Mar 6, 2018 ... long-term periodicity of ∼11 years, with different solar activities. The physical processes that occur inside the. Sun are reflected by a periodic character in terms of coronal index of coronal emission (Fe XIV 530.3 nm) during solar activity cycles. Recently, a link between the strength of photospheric magnetic ...

  13. CLOSED-FIELD CORONAL HEATING DRIVEN BY WAVE TURBULENCE

    Energy Technology Data Exchange (ETDEWEB)

    Downs, Cooper; Lionello, Roberto; Mikić, Zoran; Linker, Jon A [Predictive Science Incorporated, 9990 Mesa Rim Rd. Suite 170, San Diego, CA 92121 (United States); Velli, Marco, E-mail: cdowns@predsci.com [EPSS, UCLA, Los Angeles, CA 90095 (United States)

    2016-12-01

    To simulate the energy balance of coronal plasmas on macroscopic scales, we often require the specification of the coronal heating mechanism in some functional form. To go beyond empirical formulations and to build a more physically motivated heating function, we investigate the wave-turbulence-driven (WTD) phenomenology for the heating of closed coronal loops. Our implementation is designed to capture the large-scale propagation, reflection, and dissipation of wave turbulence along a loop. The parameter space of this model is explored by solving the coupled WTD and hydrodynamic evolution in 1D for an idealized loop. The relevance to a range of solar conditions is also established by computing solutions for over one hundred loops extracted from a realistic 3D coronal field. Due to the implicit dependence of the WTD heating model on loop geometry and plasma properties along the loop and at the footpoints, we find that this model can significantly reduce the number of free parameters when compared to traditional empirical heating models, and still robustly describe a broad range of quiet-Sun and active region conditions. The importance of the self-reflection term in producing relatively short heating scale heights and thermal nonequilibrium cycles is also discussed.

  14. Plasma effect on tunnelling, charge transfer and transient quasimolecular states

    International Nuclear Information System (INIS)

    Fisher, D V

    2003-01-01

    The influence of a dense plasma environment on electron tunnelling between two ion potential wells in collectivized states and in charge-transfer collisions is studied. We show that the tunnelling probabilities in dilute plasma (in a close ion-ion collision) and in dense plasma differ strongly. The difference is due to the mixing between Stark components of donor-ion energy levels, caused by the field of spectator ions in a dense plasma. The mixing is determined by an angle α between the nearest-neighbour ion field and the total electric field acting on the donor ion. In close ion-ion binary collisions the mixing may be considered weak. However, for most plasma ions charge transfer, electron state collectivization and transient quasimolecule formation are strongly affected by the field of spectator ions. We derive approximate analytical expressions for the distribution function of α in an ideal plasma and perform molecular dynamics simulations to find the distribution function of α in both ideal and nonideal plasmas. Both α-dependent and average mixing coefficients are determined. We have found that the mixing is strong, even in ideal plasmas, and increases further with an increase in plasma nonideality. It is shown that there is no resonant charge transfer in dense plasmas. The applicability of a transient 'dicenter' quasimolecule model for dense plasmas is discussed

  15. Radiative charge-transfer lifetime of the excited state of (NaCa)+

    International Nuclear Information System (INIS)

    Makarov, Oleg P.; Cote, R.; Michels, H.; Smith, W.W.

    2003-01-01

    New experiments were proposed recently to investigate the regime of cold atomic and molecular ion-atom collision processes in a special hybrid neutral-atom-ion trap under high-vacuum conditions. We study the collisional cooling of laser precooled Ca + ions by ultracold Na atoms. Modeling this process requires knowledge of the radiative lifetime of the excited singlet A 1 Σ + state of the (NaCa) + molecular system. We calculate the rate coefficient for radiative charge transfer using a semiclassical approach. The dipole radial matrix elements between the ground and the excited states, and the potential curves were calculated using complete active space self-consistent field and Moeller-Plesset second-order perturbation theory with an extended Gaussian basis, 6-311+G (3df). The semiclassical charge-transfer rate coefficient was averaged over a thermal Maxwellian distribution. In addition, we also present elastic collision cross sections and the spin-exchange cross section. The rate coefficient for charge transfer was found to be 2.3x10 -16 cm 3 /sec, while those for the elastic and spin-exchange cross sections were found to be several orders of magnitude higher (1.1x10 -8 cm 3 /sec and 2.3x10 -9 cm 3 /sec, respectively). This confirms our assumption that the milli-Kelvin regime of collisional cooling of calcium ions by sodium atoms is favorable with the respect to low loss of calcium ions due to the charge transfer

  16. Fast Breakdown as Coronal/Ionization Waves?

    Science.gov (United States)

    Krehbiel, P. R.; Petersen, D.; da Silva, C. L.

    2017-12-01

    Studies of high-power narrow bipolar events (NBEs) have shown they are produced by a newly-recognized breakdown process called fast positive breakdown (FPB, Rison et al., 2016, doi:10.1038/ncomms10721). The breakdown was inferred to be produced by a system of positive streamers that propagate at high speed ( ˜3-6 x 107 m/s) due to occurring in a localized region of strong electric field. The polarity of the breakdown was determined from broadband interferometer (INTF) observations of the propagation direction of its VHF radiation, which was downward into the main negative charge region of a normally-electrified storm. Subsequent INTF observations being conducted in at Kennedy Space Center in Florida have shown a much greater incidence of NBEs than in New Mexico. Among the larger dataset have been clear-cut instances of some NBEs being produced by upward breakdown that would be of negative polarity. The speed and behavior of the negative breakdown is the same as that of the fast positive, leading to it being termed fast negative breakdown (FNB). The similarity (not too mention its occurrence) is surprising, given the fact that negative streamers and breakdown develops much differently than that of positive breakdown. The question is how this happens. In this study, we compare fast breakdown characteristics to well-known streamer properties as inferred from laboratory experiments and theoretical analysis. Additionally, we begin to explore the possibility that both polarities of fast breakdown are produced by what may be called coronal or ionization waves, in which the enhanced electric field produced by streamer or coronal breakdown of either polarity propagates away from the advancing front at the speed of light into a medium that is in a metastable condition of being at the threshold of hydrometeor-mediated corona onset or other ionization processes. The wave would develop at a faster speed than the streamer breakdown that gives rise to it, and thus would be

  17. Culex coronator in coastal Georgia and South Carolina.

    Science.gov (United States)

    Moulis, Robert A; Russell, Jennifer D; Lewandowski, Henry B; Thompson, Pamela S; Heusel, Jeffrey L

    2008-12-01

    In 2007, adult Culex coronator were collected in Chatham County, Georgia, and Jasper County, South Carolina, during nuisance and disease vector surveillance efforts. A total of 75 specimens of this species were collected at 8 widely separated locations in Chatham County, Georgia, and 4 closely situated sites in Jasper County, South Carolina. These represent the first Atlantic coastal records of this species in Georgia and the first confirmed records of Cx. coronator in South Carolina.

  18. Quantum computing based on space states without charge transfer

    International Nuclear Information System (INIS)

    Vyurkov, V.; Filippov, S.; Gorelik, L.

    2010-01-01

    An implementation of a quantum computer based on space states in double quantum dots is discussed. There is no charge transfer in qubits during a calculation, therefore, uncontrolled entanglement between qubits due to long-range Coulomb interaction is suppressed. Encoding and processing of quantum information is merely performed on symmetric and antisymmetric states of the electron in double quantum dots. Other plausible sources of decoherence caused by interaction with phonons and gates could be substantially suppressed in the structure as well. We also demonstrate how all necessary quantum logic operations, initialization, writing, and read-out could be carried out in the computer.

  19. RECONNECTION-DRIVEN CORONAL-HOLE JETS WITH GRAVITY AND SOLAR WIND

    Energy Technology Data Exchange (ETDEWEB)

    Karpen, J. T.; DeVore, C. R.; Antiochos, S. K. [Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt MD 20771 (United States); Pariat, E. [LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Université, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cité, 5 place Jules Janssen, F-92195 Meudon (France)

    2017-01-01

    Coronal-hole jets occur ubiquitously in the Sun's coronal holes, at EUV and X-ray bright points associated with intrusions of minority magnetic polarity. The embedded-bipole model for these jets posits that they are driven by explosive, fast reconnection between the stressed closed field of the embedded bipole and the open field of the surrounding coronal hole. Previous numerical studies in Cartesian geometry, assuming uniform ambient magnetic field and plasma while neglecting gravity and solar wind, demonstrated that the model is robust and can produce jet-like events in simple configurations. We have extended these investigations by including spherical geometry, gravity, and solar wind in a nonuniform, coronal hole-like ambient atmosphere. Our simulations confirm that the jet is initiated by the onset of a kink-like instability of the internal closed field, which induces a burst of reconnection between the closed and external open field, launching a helical jet. Our new results demonstrate that the jet propagation is sustained through the outer corona, in the form of a traveling nonlinear Alfvén wave front trailed by slower-moving plasma density enhancements that are compressed and accelerated by the wave. This finding agrees well with observations of white-light coronal-hole jets, and can explain microstreams and torsional Alfvén waves detected in situ in the solar wind. We also use our numerical results to deduce scaling relationships between properties of the coronal source region and the characteristics of the resulting jet, which can be tested against observations.

  20. Macrospicule Jets in On-Disk Coronal Holes

    Science.gov (United States)

    Adams, M. L.; Sterling, A. C.; Moore, R. L.

    2014-01-01

    We examine the magnetic structure and dynamics of multiple jets found in coronal holes close to or on disk center. All data are from the Atmospheric Imaging Assembly (AIA) and the Helioseismic and Magnetic Imager (HMI) of the Solar Dynamics Observatory (SDO). We report on observations of six jets in an equatorial coronal hole spanning 2011 February 27 and 28. We show the evolution of these jets in AIA 193 A, examine the magnetic field configuration, and postulate the probable trigger mechanism of these events. We recently reported on another jet in the same coronal hole on 2011 February 27, approximately 13:04 Universal Time (Adams et al 2014, Astrophysical Journal, 783: 11); this jet is a previously-unrecognized variety of blowout jet. In this variety, the reconnection bright point is not made by interchange reconnection of initially-closed erupting field in the base of the jet with ambient open field. Instead, there is a miniature filament-eruption flare arcade made by internal reconnection of the legs of the erupting field.

  1. Solar origins of coronal mass ejections

    Science.gov (United States)

    Kahler, Stephen

    1987-01-01

    The large scale properties of coronal mass ejections (CMEs), such as morphology, leading edge speed, and angular width and position, have been cataloged for many events observed with coronagraphs on the Skylab, P-78, and SMM spacecraft. While considerable study has been devoted to the characteristics of the SMEs, their solar origins are still only poorly understood. Recent observational work has involved statistical associations of CMEs with flares and filament eruptions, and some evidence exists that the flare and eruptive-filament associated CMEs define two classes of events, with the former being generally more energetic. Nevertheless, it is found that eruptive-filament CMEs can at times be very energetic, giving rise to interplanetary shocks and energetic particle events. The size of the impulsive phase in a flare-associated CME seems to play no significant role in the size or speed of the CME, but the angular sizes of CMEs may correlate with the scale sizes of the 1-8 angstrom x-ray flares. At the present time, He 10830 angstrom observations should be useful in studying the late development of double-ribbon flares and transient coronal holes to yield insights into the CME aftermath. The recently available white-light synoptic maps may also prove fruitful in defining the coronal conditions giving rise to CMEs.

  2. EIT Observations of Coronal Mass Ejections

    Science.gov (United States)

    Gurman, J. B.; Fisher, Richard B. (Technical Monitor)

    2000-01-01

    Before the Solar and Heliospheric Observatory (SOHO), we had only the sketchiest of clues as to the nature and topology of coronal mass ejections (CMEs) below 1.1 - 1.2 solar radii. Occasionally, dimmings (or 'transient coronal holes') were observed in time series of soft X-ray images, but they were far less frequent than CME's. Simply by imaging the Sun frequently and continually at temperatures of 0.9 - 2.5 MK we have stumbled upon a zoo of CME phenomena in this previously obscured volume of the corona: (1) waves, (2) dimmings, and (3) a great variety of ejecta. In the three and a half years since our first observations of coronal waves associated with CME's, combined Large Angle Spectroscopic Coronagraph (LASCO) and extreme ultra-violet imaging telescope (EIT) synoptic observations have become a standard prediction tool for space weather forecasters, but our progress in actually understanding the CME phenomenon in the low corona has been somewhat slower. I will summarize the observations of waves, hot (> 0.9 MK) and cool ejecta, and some of the interpretations advanced to date. I will try to identify those phenomena, analysis of which could most benefit from the spectroscopic information available from ultraviolet coronograph spectrometer (UVCS) observations.

  3. Excited state and charge-carrier dynamics in perovskite solar cell materials

    Science.gov (United States)

    Ponseca, Carlito S., Jr.; Tian, Yuxi; Sundström, Villy; Scheblykin, Ivan G.

    2016-02-01

    Organo-metal halide perovskites (OMHPs) have attracted enormous interest in recent years as materials for application in optoelectronics and solar energy conversion. These hybrid semiconductors seem to have the potential to challenge traditional silicon technology. In this review we will give an account of the recent development in the understanding of the fundamental light-induced processes in OMHPs from charge-photo generation, migration of charge carries through the materials and finally their recombination. Our and other literature reports on time-resolved conductivity, transient absorption and photoluminescence properties are used to paint a picture of how we currently see the fundamental excited state and charge-carrier dynamics. We will also show that there is still no fully coherent picture of the processes in OMHPs and we will indicate the problems to be solved by future research.

  4. Magnetism tuned by the charge states of defects in bulk C-doped SnO2 materials.

    Science.gov (United States)

    Lu, Ying-Bo; Ling, Z C; Cong, Wei-Yan; Zhang, Peng

    2015-10-21

    To analyze the controversial conclusions on the magnetism of C-doped SnO2 (SnO2:C) bulk materials between theoretical calculations and experimental observations, we propose the critical role of the charge states of defects in the geometric structures and magnetism, and carry out a series of first principle calculations. By changing the charge states, we can influence Bader charge distributions and atomic orbital occupancies in bulk SnO2:C systems, which consequently conduct magnetism. In all charged SnO2:C supercells, C-2px/py/pz electron occupancies are significantly changed by the charge self-regulation, and thus they make the C-2p orbitals spin polarized, which contribute to the dominant magnetic moment of the system. When the concentration of C dopant in the SnO2 supercell increases, the charge redistribution assigns extra electrons averagely to each dopant, and thus effectively modulates the magnetism. These findings provide an experimentally viable way for controlling the magnetism in these systems.

  5. Coronal pulp biomarker: A lesser known age estimation modality

    Directory of Open Access Journals (Sweden)

    Smrithi D Veera

    2014-01-01

    Full Text Available Introduction: The evolving state of art digital technology currently available is opening new avenues in forensic odontology for age estimation methods which are subject to debate in terms of accuracy and precision. A study was carried to analyze efficacy and practical application for age estimation using digital panoramic radiographs on South Indian population. Aims and Objectives: 1. To study reduction of coronal pulp chamber using Tooth Coronal Index (TCI on panoramic radiographs and correlate with chronologic age. 2. To establish accuracy of digital panoramic radiographs as a simple, non-invasive tool. Materials and Methods: The study illustrates the potential value of a little known aging method. The study groups comprised a total of 100 subjects of both sexes in age range of 20 and 60 years each who were subjected to panoramic radiography. A panoramic radiographic examination using digital panoramic machine was conducted on selected individuals. The TCI was calibrated using AGFA computer software for accuracy and precision. The values obtained were subjected to regression analysis, results calculated and correlated with chronologic age. In the present study a population of known age was studied and subjected to digital panoramic radiographic examination. The correlation between reduction of coronal pulp cavity and chronological age was examined. TCI was computed for each tooth and regressed on real age. Statistical Analysis Used: Pearson correlation co-efficient was used to find the significance of relationship between age and TCI. Regression analysis has been used for predicting age using TCI for premolar and molar. Inaccuracy and bias have been determined to assess the precision of prediction equations. Results and Conclusion: Prediction potential of TCI comes down for ages above 50 years and is comfortably good below 50 years without much difference between premolars and molars. This study demonstrates the potential value of TCI for age

  6. A strong steric hindrance effect on ground state, excited state, and charge separated state properties of a CuI-diimine complex captured by X-ray transient absorption spectroscopy

    DEFF Research Database (Denmark)

    Huang, J.; Mara, M.W.; Stickrath, A.B.

    2014-01-01

    of phenanthroline. The structural dynamics of the photoinduced charge transfer process in the [CuI(dppS)2]+/TiO2 hybrid is also investigated, which suggests a more restricted environment for the complex upon binding to TiO2 NPs. Moreover, the Cu-N bond length of the oxidized state of [CuI(dppS)2]+ after electron...... dynamics and structures as well as those of the charge separated state resulting from the interfacial electron injection from the MLCT state to TiO2 nanoparticles (NPs). The OTA results show the absence of the sub-picosecond component previously assigned as the time constant for flattening, while the two...... injection to TiO2 NPs shortens by 0.05 Å compared to that in the ground state. The interpretation of these observed structural changes associated with excited and charge separated states will be discussed. These results not only set an example for applying XTA in capturing the intermediate structure...

  7. Rendering high charge density of states in ionic liquid-gated MoS 2 transistors

    NARCIS (Netherlands)

    Lee, Y.; Lee, J.; Kim, S.; Park, H.S.

    2014-01-01

    We investigated high charge density of states (DOS) in the bandgap of MoS2 nanosheets with variable temperature measurements on ionic liquid-gated MoS2 transistors. The thermally activated charge transport indicates that the electrical current in the two-dimensional MoS 2 nanosheets under high

  8. Solar Coronal Loops Associated with Small-scale Mixed Polarity Surface Magnetic Fields

    International Nuclear Information System (INIS)

    Chitta, L. P.; Peter, H.; Solanki, S. K.; Barthol, P.; Gandorfer, A.; Gizon, L.; Hirzberger, J.; Riethmüller, T. L.; Noort, M. van; Rodríguez, J. Blanco; Iniesta, J. C. Del Toro; Suárez, D. Orozco; Schmidt, W.; Pillet, V. Martínez; Knölker, M.

    2017-01-01

    How and where are coronal loops rooted in the solar lower atmosphere? The details of the magnetic environment and its evolution at the footpoints of coronal loops are crucial to understanding the processes of mass and energy supply to the solar corona. To address the above question, we use high-resolution line-of-sight magnetic field data from the Imaging Magnetograph eXperiment instrument on the Sunrise balloon-borne observatory and coronal observations from the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory of an emerging active region. We find that the coronal loops are often rooted at the locations with minor small-scale but persistent opposite-polarity magnetic elements very close to the larger dominant polarity. These opposite-polarity small-scale elements continually interact with the dominant polarity underlying the coronal loop through flux cancellation. At these locations we detect small inverse Y-shaped jets in chromospheric Ca ii H images obtained from the Sunrise Filter Imager during the flux cancellation. Our results indicate that magnetic flux cancellation and reconnection at the base of coronal loops due to mixed polarity fields might be a crucial feature for the supply of mass and energy into the corona.

  9. Solar Coronal Loops Associated with Small-scale Mixed Polarity Surface Magnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    Chitta, L. P.; Peter, H.; Solanki, S. K.; Barthol, P.; Gandorfer, A.; Gizon, L.; Hirzberger, J.; Riethmüller, T. L.; Noort, M. van [Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany); Rodríguez, J. Blanco [Grupo de Astronomía y Ciencias del Espacio, Universidad de Valencia, E-46980 Paterna, Valencia (Spain); Iniesta, J. C. Del Toro; Suárez, D. Orozco [Instituto de Astrofísica de Andalucía (CSIC), Apartado de Correos 3004, E-18080 Granada (Spain); Schmidt, W. [Kiepenheuer-Institut für Sonnenphysik, Schöneckstr. 6, D-79104 Freiburg (Germany); Pillet, V. Martínez [National Solar Observatory, 3665 Discovery Drive, Boulder, CO 80303 (United States); Knölker, M., E-mail: chitta@mps.mpg.de [High Altitude Observatory, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307-3000 (United States)

    2017-03-01

    How and where are coronal loops rooted in the solar lower atmosphere? The details of the magnetic environment and its evolution at the footpoints of coronal loops are crucial to understanding the processes of mass and energy supply to the solar corona. To address the above question, we use high-resolution line-of-sight magnetic field data from the Imaging Magnetograph eXperiment instrument on the Sunrise balloon-borne observatory and coronal observations from the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory of an emerging active region. We find that the coronal loops are often rooted at the locations with minor small-scale but persistent opposite-polarity magnetic elements very close to the larger dominant polarity. These opposite-polarity small-scale elements continually interact with the dominant polarity underlying the coronal loop through flux cancellation. At these locations we detect small inverse Y-shaped jets in chromospheric Ca ii H images obtained from the Sunrise Filter Imager during the flux cancellation. Our results indicate that magnetic flux cancellation and reconnection at the base of coronal loops due to mixed polarity fields might be a crucial feature for the supply of mass and energy into the corona.

  10. An on-line estimation of battery pack parameters and state-of-charge using dual filters based on pack model

    International Nuclear Information System (INIS)

    Zhang, Xu; Wang, Yujie; Yang, Duo; Chen, Zonghai

    2016-01-01

    Accurate estimation of battery pack state-of-charge plays a very important role for electric vehicles, which directly reflects the behavior of battery pack usage. However, the inconsistency of battery makes the estimation of battery pack state-of-charge different from single cell. In this paper, to estimate the battery pack state-of-charge on-line, the definition of battery pack is proposed, and the relationship between the total available capacity of battery pack and single cell is put forward to analyze the energy efficiency influenced by battery inconsistency, then a lumped parameter battery model is built up to describe the dynamic behavior of battery pack. Furthermore, the extend Kalman filter-unscented Kalman filter algorithm is developed to identify the parameters of battery pack and forecast state-of-charge concurrently. The extend Kalman filter is applied to update the battery pack parameters by real-time measured data, while the unscented Kalman filter is employed to estimate the battery pack state-of-charge. Finally, the proposed approach is verified by experiments operated on the lithium-ion battery under constant current condition and the dynamic stress test profiles. Experimental results indicate that the proposed method can estimate the battery pack state-of-charge with high accuracy. - Highlights: • A novel space state equation is built to describe the pack dynamic behavior. • The dual filters method is used to estimate the pack state-of-charge. • Battery inconsistency is considered to analyze the pack usage efficiency. • The accuracy of the proposed method is verified under different conditions.

  11. Decision-making in a death investigation: Emotion, families and the coroner.

    Science.gov (United States)

    Tait, Gordon; Carpenter, Belinda; Quadrelli, Carol; Barnes, Michael

    2016-03-01

    The role of the coroner in common law countries such as Australia, England, Canada and New Zealand is to preside over death investigations where there is uncertainty as to the manner of death, a need to identify the deceased, a death of unknown cause, or a violent or unnatural death. The vast majority of these deaths are not suspicious and thus require coroners to engage with grieving families who have been thrust into a legal process through the misfortune of a loved one's sudden or unexpected death. In this research, 10 experienced coroners discussed how they negotiated the grief and trauma evident in a death investigation. In doing so, they articulated two distinct ways in which legal officers engaged with emotions, which are also evident in the literature. The first engages the script of judicial dispassion, articulating a hierarchical relationship between reason and emotion, while the second introduces an ethic of care via the principles of therapeutic jurisprudence, and thus offers a challenge to the role of emotion in the personae of the professional judicial officer. By using Hochschild's work on the sociology of emotions, this article discusses the various ways in which coroners manage the emotion of a death investigation through emotion work. While emotional distance may be an understandable response by coroners to the grief and trauma experienced by families and directed at cleaner coronial decision-making, the article concludes that coroners may be better served by offering emotions such as sympathy, consideration and compassion directly to the family in those situations where families are struggling to accept, or are resistant to, coroners' decisions.

  12. Examining the Properties of Jets in Coronal Holes

    Science.gov (United States)

    Gaulle, Owen; Adams, Mitzi L.; Tennant, A. F.

    2012-01-01

    We examined both X-ray and Magnetic field data in order to determine if there is a correlation between emerging magnetic flux and the production of Coronal jets. It was proposed that emerging flux can be a trigger to a coronal jet. The jet is thought to be caused when local bipoles reconnect or when a region of magnetic polarity emerges through a uniform field. In total we studied 15 different jets that occurred over a two day period starting 2011-02-27 00:00:00 UTC and ending 2011-02-28 23:59:55 UTC. All of the jets were contained within a coronal hole that was centered on the disk. Of the 15 that we studied 6 were shown to have an increase of magnetic flux within one hour prior to the creation of the jet and 10 were within 3 hours before the event.

  13. Superposition Principle in Auger Recombination of Charged and Neutral Multicarrier States in Semiconductor Quantum Dots.

    Science.gov (United States)

    Wu, Kaifeng; Lim, Jaehoon; Klimov, Victor I

    2017-08-22

    Application of colloidal semiconductor quantum dots (QDs) in optical and optoelectronic devices is often complicated by unintentional generation of extra charges, which opens fast nonradiative Auger recombination pathways whereby the recombination energy of an exciton is quickly transferred to the extra carrier(s) and ultimately dissipated as heat. Previous studies of Auger recombination have primarily focused on neutral and, more recently, negatively charged multicarrier states. Auger dynamics of positively charged species remains more poorly explored due to difficulties in creating, stabilizing, and detecting excess holes in the QDs. Here we apply photochemical doping to prepare both negatively and positively charged CdSe/CdS QDs with two distinct core/shell interfacial profiles ("sharp" versus "smooth"). Using neutral and charged QD samples we evaluate Auger lifetimes of biexcitons, negative and positive trions (an exciton with an extra electron or a hole, respectively), and multiply negatively charged excitons. Using these measurements, we demonstrate that Auger decay of both neutral and charged multicarrier states can be presented as a superposition of independent elementary three-particle Auger events. As one of the manifestations of the superposition principle, we observe that the biexciton Auger decay rate can be presented as a sum of the Auger rates for independent negative and positive trion pathways. By comparing the measurements on the QDs with the "sharp" versus "smooth" interfaces, we also find that while affecting the absolute values of Auger lifetimes, manipulation of the shape of the confinement potential does not lead to violation of the superposition principle, which still allows us to accurately predict the biexciton Auger lifetimes based on the measured negative and positive trion dynamics. These findings indicate considerable robustness of the superposition principle as applied to Auger decay of charged and neutral multicarrier states

  14. Intercalation pathway in many-particle LiFePO4 electrode revealed by nanoscale state-of-charge mapping.

    Science.gov (United States)

    Chueh, William C; El Gabaly, Farid; Sugar, Joshua D; Bartelt, Norman C; McDaniel, Anthony H; Fenton, Kyle R; Zavadil, Kevin R; Tyliszczak, Tolek; Lai, Wei; McCarty, Kevin F

    2013-03-13

    The intercalation pathway of lithium iron phosphate (LFP) in the positive electrode of a lithium-ion battery was probed at the ∼40 nm length scale using oxidation-state-sensitive X-ray microscopy. Combined with morphological observations of the same exact locations using transmission electron microscopy, we quantified the local state-of-charge of approximately 450 individual LFP particles over nearly the entire thickness of the porous electrode. With the electrode charged to 50% state-of-charge in 0.5 h, we observed that the overwhelming majority of particles were either almost completely delithiated or lithiated. Specifically, only ∼2% of individual particles were at an intermediate state-of-charge. From this small fraction of particles that were actively undergoing delithiation, we conclude that the time needed to charge a particle is ∼1/50 the time needed to charge the entire particle ensemble. Surprisingly, we observed a very weak correlation between the sequence of delithiation and the particle size, contrary to the common expectation that smaller particles delithiate before larger ones. Our quantitative results unambiguously confirm the mosaic (particle-by-particle) pathway of intercalation and suggest that the rate-limiting process of charging is initiating the phase transformation by, for example, a nucleation-like event. Therefore, strategies for further enhancing the performance of LFP electrodes should not focus on increasing the phase-boundary velocity but on the rate of phase-transformation initiation.

  15. Administrative charges in pensions in Chile, Malaysia, Zambia, and the United States

    OpenAIRE

    Valdes-Prieto, Salvador

    1994-01-01

    The author offers a framework for an international comparison of charges in mandatory and private pension systems, and in state-run and privately managed systems. Such comparisons make it possible to determine which combinations of quality and cost make the most sense in pension services. He finds that: 1) Charges in the private annuity industry are much higher than other components of the pension package, and much higher than publicly provided annuities in the US; 2) comparing the collection...

  16. Charge-Transfer States in Organic Solar Cells: Understanding the Impact of Polarization, Delocalization, and Disorder

    KAUST Repository

    Zheng, Zilong

    2017-05-08

    We investigate the impact of electronic polarization, charge delocalization, and energetic disorder on the charge-transfer (CT) states formed at a planar C60/pentacene interface. The ability to examine large complexes containing up to seven pentacene molecules and three C60 molecules allows us to take explicitly into account the electronic polarization effects. These complexes are extracted from a bilayer architecture modeled by molecular dynamics simulations and evaluated by means of electronic-structure calculations based on long-range-separated functionals (ωB97XD and BNL) with optimized range-separation parameters. The energies of the lowest charge-transfer states derived for the large complexes are in very good agreement with the experimentally reported values. The average singlet-triplet energy splittings of the lowest CT states are calculated not to exceed 10 meV. The rates of geminate recombination as well as of dissociation of the triplet excitons are also evaluated. In line with experiment, our results indicate that the pentacene triplet excitons generated through singlet fission can dissociate into separated charges on a picosecond time scale, despite the fact that their energy in C60/pentacene heterojunctions is slightly lower than the energies of the lowest CT triplet states.

  17. Radio emission from coronal and interplanetary shocks

    International Nuclear Information System (INIS)

    Cane, H.V.

    1987-01-01

    Observational data on coronal and interplanetary (IP) type II burst events associated with shock-wave propagation are reviewed, with a focus on the past and potential future contributions of space-based observatories. The evidence presented by Cane (1983 and 1984) in support of the hypothesis that the coronal (metric) and IP (kilometric) bursts are due to different shocks is summarized, and the fast-drift kilometric events seen at the same time as metric type II bursts (and designated shock-accelerated or shock-associated events) are characterized. The need for further observations at 0.5-20 MHz is indicated. 20 references

  18. Multidetector CT enteroclysis: comparison of the reading performance for axial and coronal views

    International Nuclear Information System (INIS)

    Schmidt, Sabine; Chalaron, Marc; Schnyder, Pierre; Denys, Alban; Chevallier, Patrick; Bessoud, Bertrand; Verdun, Francis R.; Frascarolo, Philippe

    2005-01-01

    The purpose of this study was to compare the diagnostic performance of axial and coronal views in multidetector CT enteroclysis (MDCTE). We retrospectively evaluated 48 patients with pathological correlation investigated by MDCTE for small bowel disorders. After nasojejunal administration of 2 l of 5% methylcellulose axial arterial and venous acquisition of MDCTE was followed by coronal reconstructions using equal slice thicknesses of 2.5 mm with 2 mm increments. Spatial resolution of both planes was evaluated by phantom. Three radiologists independently read axial and coronal images concerning 12 pathological features. The interobserver agreement and time of reading was calculated. Sensitivity and specificity resulted from comparison with histopathology (n=39) or follow-up (n=9). Phantom study revealed higher spatial resolution for axial than coronal views, whatever reconstruction interval was used. However, spatial frequency always remained high. Most pathological signs, such as bowel wall thickening (BWT), bowel wall enhancement (BWE) and intraperitoneal fluid (IPF), showed better interobserver agreement on axial than coronal views (BWT: 0.61 vs. 0.44; BWE: 0.56 vs. 0.5; IPF:0.53 vs. 0.43). The Wilcoxon signed-rank test revealed significantly higher sensitivity for axial than coronal views (P=0.0453); the time of reading was significantly shorter for the latter (P=0.0146). The diagnostic value of axial slices is superior to coronal reconstructions despite the reduced data volume and display of the physiological course of bowel loops on the coronal plane. (orig.)

  19. Coronal mass ejections and coronal structures

    International Nuclear Information System (INIS)

    Hildner, E.; Bassi, J.; Bougeret, J.L.

    1986-01-01

    Research on coronal mass ejections (CMF) took a variety of forms, both observational and theoretical. On the observational side there were: case studies of individual events, in which it was attempted to provide the most complete descriptions possible, using correlative observations in diverse wavelengths; statistical studies of the properties of CMEs and their associated activity; observations which may tell us about the initiation of mass ejections; interplanetary observations of associated shocks and energetic particles; observations of CMEs traversing interplanetary space; and the beautiful synoptic charts which show to what degree mass ejections affect the background corona and how rapidly (if at all) the corona recovers its pre-disturbance form. These efforts are described in capsule form with an emphasis on presenting pictures, graphs, and tables so that the reader can form a personal appreciation of the work and its results

  20. More Macrospicule Jets in On-Disk Coronal Holes

    Science.gov (United States)

    Adams, M. L.; Sterling, A. C.; Moore, R. L.

    2015-01-01

    We examine the magnetic structure and dynamics of multiple jets found in coronal holes close to or on disk center. All data are from the Atmospheric Imaging Assembly (AIA) and the Helioseismic and Magnetic Imager (HMI) of the Solar Dynamics Observatory (SDO). We report on observations of about ten jets in an equatorial coronal hole spanning 2011 February 27 and 28. We show the evolution of these jets in AIA 193 A, examine the magnetic field configuration and flux changes in the jet area, and discuss the probable trigger mechanism of these events. We reported on another jet in this same coronal hole on 2011 February 27, (is) approximately 13:04 UT (Adams et al 2014, ApJ, 783: 11). That jet is a previously-unrecognized variety of blowout jet, in which the base-edge bright point is a miniature filament-eruption flare arcade made by internal reconnection of the legs of the erupting field. In contrast, in the presently-accepted 'standard' picture for blowout jets, the base-edge bright point is made by interchange reconnection of initially-closed erupting jet-base field with ambient open field. This poster presents further evidence of the production of the base-edge bright point in blowout jets by internal reconnection. Our observations suggest that most of the bigger and brighter EUV jets in coronal holes are blowout jets of the new-found variety.

  1. Automated coronal hole identification via multi-thermal intensity segmentation

    Science.gov (United States)

    Garton, Tadhg M.; Gallagher, Peter T.; Murray, Sophie A.

    2018-01-01

    Coronal holes (CH) are regions of open magnetic fields that appear as dark areas in the solar corona due to their low density and temperature compared to the surrounding quiet corona. To date, accurate identification and segmentation of CHs has been a difficult task due to their comparable intensity to local quiet Sun regions. Current segmentation methods typically rely on the use of single Extreme Ultra-Violet passband and magnetogram images to extract CH information. Here, the coronal hole identification via multi-thermal emission recognition algorithm (CHIMERA) is described, which analyses multi-thermal images from the atmospheric image assembly (AIA) onboard the solar dynamics observatory (SDO) to segment coronal hole boundaries by their intensity ratio across three passbands (171 Å, 193 Å, and 211 Å). The algorithm allows accurate extraction of CH boundaries and many of their properties, such as area, position, latitudinal and longitudinal width, and magnetic polarity of segmented CHs. From these properties, a clear linear relationship was identified between the duration of geomagnetic storms and coronal hole areas. CHIMERA can therefore form the basis of more accurate forecasting of the start and duration of geomagnetic storms.

  2. Analysis of Solar Coronal Holes with Synoptic Magnetogram Data

    Science.gov (United States)

    Canner, A.; Kim, T. K.; Pogorelov, N.; Yalim, M. S.

    2017-12-01

    Coronal holes are regions in which the magnetic field of the Sun is open with high magnetic flux and low plasma density. Because of the low plasma beta in these regions, the open field lines transport plasma from the Sun throughout the heliosphere. Coronal hole area is closely related to the expansion factor of the magnetic flux tube, as demonstrated by Tokumaru et al. (2017). Following the approach of Tokumaru et al. (2017), we employ a potential field source surface model to identify the open field regions on the photosphere and estimate the area and expansion factor for each coronal hole. While Tokumaru et al. (2017) analyzed synoptic maps from Kitt Peak National Observatory for the period 1995-2011, we use different magnetograph observations with higher spatial resolution (e.g., SOHO-MDI) for the same time period. We compare the coronal hole area - expansion factor relationship with the original results of Tokumaru et al (2017). This work was supported by the NSF-funded Research Experience for Undergraduates program "Solar and Heliospheric Physics at UAH and MSFC" run by the University of Alabama in Huntsville in partnership with the Marshall Space Flight Center through grant AGS-1460767.

  3. Coronal Activity in the R CrA T Association

    Science.gov (United States)

    Patten, Brian M.; Oliversen, Ronald J. (Technical Monitor)

    2005-01-01

    Brian Patten is the Principal Investigator of the NASA ROSS-ADP project Coronal Activity in the R CrA T Association. For this project we have extracted net counts and variability information for all of the X-ray sources found in 23 archival ROSAT PSPC and HRI images in the region of the R CrA T association. These data have been merged with an extensive database of optical and near-infrared photometry, optical spectroscopy, and parallax data. These data have been used to (1) identify new association members and clarify the membership status of a number of previously suspected members of the association, and (2) derive, for the first time, an accurate coronal luminosity function for the T Tauri members of this T association and make direct comparisons between the coronal luminosity functions for other T associations and those of large clusters. We have used our survey data to assess (a) the importance of the star-formation environment in initial coronal activity levels, (b) the effects of PMS evolution on dynamo activity as a function of mass and age, and (c) the level of contamination by field post-T Tauri stars on association membership surveys.

  4. Localized chemical switching of the charge state of nitrogen-vacancy luminescence centers in diamond

    Energy Technology Data Exchange (ETDEWEB)

    Shanley, Toby W.; Martin, Aiden A.; Aharonovich, Igor, E-mail: Igor.Aharonovich@uts.edu.au; Toth, Milos, E-mail: Milos.Toth@uts.edu.au [School of Physics and Advanced Materials, University of Technology, Sydney, P.O. Box 123, Broadway, New South Wales 2007 (Australia)

    2014-08-11

    We present a direct-write chemical technique for controlling the charge state of near-surface nitrogen vacancy centers (NVs) in diamond by surface fluorination. Fluorination of H-terminated diamond is realized by electron beam stimulated desorption of H{sub 2}O in the presence of NF{sub 3} and verified with environmental photoyield spectroscopy (EPYS) and photoluminescence (PL) spectroscopy. PL spectra of shallow NVs in H- and F-terminated nanodiamonds show the expected dependence of the NV charge state on their energetic position with respect to the Fermi-level. EPYS reveals a corresponding difference between the ionization potential of H- and F-terminated diamond. The electron beam fluorination process is highly localized and can be used to fluorinate H-terminated diamond, and to increase the population of negatively charged NV centers.

  5. Kalman-variant estimators for state of charge in lithium-sulfur batteries

    DEFF Research Database (Denmark)

    Propp, Karsten; Auger, Daniel J.; Fotouhi, Abbas

    2017-01-01

    Lithium-sulfur batteries are now commercially available, offering high specific energy density, low production costs and high safety. However, there is no commercially-available battery management system for them, and there are no published methods for determining state of charge in situ...

  6. The Relation between Coronal Holes and Coronal Mass Ejections during the Rise, Maximum, and Declining Phases of Solar Cycle 23

    Science.gov (United States)

    Mohamed, A. A.; Gopalswamy, N; Yashiro, S.; Akiyama, S.; Makela, P.; Xie, H.; Jung, H.

    2012-01-01

    We study the interaction between coronal holes (CHs) and coronal mass ejections (CMEs) using a resultant force exerted by all the coronal holes present on the disk and is defined as the coronal hole influence parameter (CHIP). The CHIP magnitude for each CH depends on the CH area, the distance between the CH centroid and the eruption region, and the average magnetic field within the CH at the photospheric level. The CHIP direction for each CH points from the CH centroid to the eruption region. We focus on Solar Cycle 23 CMEs originating from the disk center of the Sun (central meridian distance =15deg) and resulting in magnetic clouds (MCs) and non-MCs in the solar wind. The CHIP is found to be the smallest during the rise phase for MCs and non-MCs. The maximum phase has the largest CHIP value (2.9 G) for non-MCs. The CHIP is the largest (5.8 G) for driverless (DL) shocks, which are shocks at 1 AU with no discernible MC or non-MC. These results suggest that the behavior of non-MCs is similar to that of the DL shocks and different from that of MCs. In other words, the CHs may deflect the CMEs away from the Sun-Earth line and force them to behave like limb CMEs with DL shocks. This finding supports the idea that all CMEs may be flux ropes if viewed from an appropriate vantage point.

  7. Electroweak-charged bound states as LHC probes of hidden forces

    Science.gov (United States)

    Li, Lingfeng; Salvioni, Ennio; Tsai, Yuhsin; Zheng, Rui

    2018-01-01

    We explore the LHC reach on beyond-the-standard model (BSM) particles X associated with a new strong force in a hidden sector. We focus on the motivated scenario where the SM and hidden sectors are connected by fermionic mediators ψ+,0 that carry SM electroweak charges. The most promising signal is the Drell-Yan production of a ψ±ψ¯ 0 pair, which forms an electrically charged vector bound state ϒ± due to the hidden force and later undergoes resonant annihilation into W±X . We analyze this final state in detail in the cases where X is a real scalar ϕ that decays to b b ¯, or a dark photon γd that decays to dileptons. For prompt X decays, we show that the corresponding signatures can be efficiently probed by extending the existing ATLAS and CMS diboson searches to include heavy resonance decays into BSM particles. For long-lived X , we propose new searches where the requirement of a prompt hard lepton originating from the W boson ensures triggering and essentially removes any SM backgrounds. To illustrate the potential of our results, we interpret them within two explicit models that contain strong hidden forces and electroweak-charged mediators, namely λ -supersymmetry (SUSY) and non-SUSY ultraviolet extensions of the twin Higgs model. The resonant nature of the signals allows for the reconstruction of the mass of both ϒ± and X , thus providing a wealth of information about the hidden sector.

  8. State-selective charge transfer cross sections for light ion impact of atomic hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Schultz, D. R. [University of North Texas; Stancil, Phillip C. [University of Georgia, Athens; Havener, C. C. [Oak Ridge National Laboratory (ORNL)

    2015-01-01

    Owing to the utility of diagnosing plasma properties such as impurity concentration and spatial distribution, and plasma temperature and rotation, by detection of photon emission following capture of electrons from atomic hydrogen to excited states of multiply charged ions, new calculations of state-selective charge transfer involving light ions have been carried out using the atomic orbital close-coupling and the classical trajectory Monte Carlo methods. By comparing these with results of other approaches applicable in a lower impact energy regime, and by benchmarking them using key experimental data, knowledge of the cross sections can be made available across the range parameters needed by fusion plasma diagnostics.

  9. Solar Magnetic Carpet III: Coronal Modelling of Synthetic Magnetograms

    Science.gov (United States)

    Meyer, K. A.; Mackay, D. H.; van Ballegooijen, A. A.; Parnell, C. E.

    2013-09-01

    This article is the third in a series working towards the construction of a realistic, evolving, non-linear force-free coronal-field model for the solar magnetic carpet. Here, we present preliminary results of 3D time-dependent simulations of the small-scale coronal field of the magnetic carpet. Four simulations are considered, each with the same evolving photospheric boundary condition: a 48-hour time series of synthetic magnetograms produced from the model of Meyer et al. ( Solar Phys. 272, 29, 2011). Three simulations include a uniform, overlying coronal magnetic field of differing strength, the fourth simulation includes no overlying field. The build-up, storage, and dissipation of magnetic energy within the simulations is studied. In particular, we study their dependence upon the evolution of the photospheric magnetic field and the strength of the overlying coronal field. We also consider where energy is stored and dissipated within the coronal field. The free magnetic energy built up is found to be more than sufficient to power small-scale, transient phenomena such as nanoflares and X-ray bright points, with the bulk of the free energy found to be stored low down, between 0.5 - 0.8 Mm. The energy dissipated is currently found to be too small to account for the heating of the entire quiet-Sun corona. However, the form and location of energy-dissipation regions qualitatively agree with what is observed on small scales on the Sun. Future MHD modelling using the same synthetic magnetograms may lead to a higher energy release.

  10. Calculation of Ion Charge State Distributions After Inner-Shell Ionization in Xe Atom

    International Nuclear Information System (INIS)

    Mohammedein, A.M.; Ghoneim, A.A.; Kandil, M.K.; Kadad, I.M.

    2009-01-01

    The vacancy cascades following initial inner-shell vacancies in single and multi-ionized atoms often lead to highly charged residual ions. The inner-shell vacancy produced by ionization processes may decay by either a radiative or non-radiative transition. In addition to the vacancy filling processes, there is an electron shake off process due to the change of core potential of the atom. In the calculation of vacancy cascades, the radiative (x-ray) and non-radiative (Auger and Coster-Kronig) branching ratios give valuable information on the de-excitation dynamics of an atom with inner-shell vacancy. The production of multi-charged ions yield by the Auger cascades following inner shell ionization of an atom has been studied both experimentally and theoretically. Multi-charged Xe ions following de-excitation of K, L 1 , L 2,3 , M 1 , M 2,3 and M 4,5 subshell vacancies are calculated using Monte-Carlo algorithm to simulate the vacancy cascade development. Fluorescence yield (radiative) and Auger, Coster- Kronig yield (non- radiative) are evaluated. The decay of K hole state through radiative transitions is found to be more probable than non-radiative transitions in the first step of de-excitation. On the other hand, the decay of L, M vacancies through non-radiative transitions are more probable. The K shell ionization in Xe atom mainly yields Xe 7+ , Xe 8+ , Xe 9+ and Xe 1 0 + ions, and the charged X 8+ ions are the highest. The main product from the L 1 shell ionization is found to be Xe 8+ , Xe 9+ ions, while the charged Xe 8+ ions predominate at L 2,3 hole states. The charged Xe 6+ , Xe 7+ and Xe 8+ ions mainly yield from 3s 1/2 and 3p 1/2 , 3/2 ionization, while Xe in 3d 3/2 , 5/2 hole states mainly turns into Xe 4+ and Xe 5+ ions. The present results are found to agree well with the experimental data. (author)

  11. Excited state and charge-carrier dynamics in perovskite solar cell materials

    International Nuclear Information System (INIS)

    Ponseca, Carlito S Jr; Tian, Yuxi; Sundström, Villy; Scheblykin, Ivan G

    2016-01-01

    Organo-metal halide perovskites (OMHPs) have attracted enormous interest in recent years as materials for application in optoelectronics and solar energy conversion. These hybrid semiconductors seem to have the potential to challenge traditional silicon technology. In this review we will give an account of the recent development in the understanding of the fundamental light-induced processes in OMHPs from charge-photo generation, migration of charge carries through the materials and finally their recombination. Our and other literature reports on time-resolved conductivity, transient absorption and photoluminescence properties are used to paint a picture of how we currently see the fundamental excited state and charge-carrier dynamics. We will also show that there is still no fully coherent picture of the processes in OMHPs and we will indicate the problems to be solved by future research. (topical review)

  12. Does correction of preoperative coronal imbalance make a difference in outcomes of adult patients with deformity?

    Science.gov (United States)

    Daubs, Michael D; Lenke, Lawrence G; Bridwell, Keith H; Kim, Yongjung J; Hung, Man; Cheh, Gene; Koester, Linda A

    2013-03-15

    Retrospective study with prospectively collected outcomes data. Determine the significance of coronal balance on spinal deformity surgery outcomes. Sagittal balance has been confirmed as an important radiographic parameter correlating with adult deformity treatment outcomes. The significance of coronal balance on functional outcomes is less clear. Eighty-five patients with more than 4 cm of coronal imbalance who underwent reconstructive spinal surgery were evaluated to determine the significance of coronal balance on functional outcomes as measured with the Oswestry Disability Index (ODI) and Scoliosis Research Society outcomes questionnaires. Sixty-two patients had combined coronal (>4 cm) and sagittal imbalance (>5 cm), while 23 patients had coronal imbalance alone. Postoperatively, 85% of patients demonstrated improved coronal balance. The mean improvement in the coronal C7 plumb line was 26 mm for a mean correction of 42%. The mean preoperative sagittal C7 plumb line in patients with combined coronal and sagittal imbalance was 118 mm (range, 50-310 mm) and improved to a mean 49 mm. The mean preoperative and postoperative ODI scores were 42 (range, 0-90) and 27 (range, 0-78), for a mean improvement of 15 (36%) (P = 0.00001; 95% CI, 12-20). The mean Scoliosis Research Society scores improved by 17 points (29%) (P = 0.00). Younger age (P = 0.008) and improvement in sagittal balance (P = 0.014) were positive predictors for improved ODI scores. Improvement in sagittal balance (P = 0.010) was a positive predictor for improved Scoliosis Research Society scores. In patients with combined coronal and sagittal imbalance, improvement in sagittal balance was the most significant predictor for improved ODI scores (P = 0.009). In patients with preoperative coronal imbalance alone, improvement in coronal balance trended toward, but was not a significant predictor for improved ODI (P = 0.092). Sagittal balance improvement is the strongest predictor of improved outcomes in

  13. Pressure dependence of excited-state charge-carrier dynamics in organolead tribromide perovskites

    Science.gov (United States)

    Liu, X. C.; Han, J. H.; Zhao, H. F.; Yan, H. C.; Shi, Y.; Jin, M. X.; Liu, C. L.; Ding, D. J.

    2018-05-01

    Excited-state charge-carrier dynamics governs the performance of organometal trihalide perovskites (OTPs) and is strongly influenced by the crystal structure. Characterizing the excited-state charge-carrier dynamics in OTPs under high pressure is imperative for providing crucial insights into structure-property relations. Here, we conduct in situ high-pressure femtosecond transient absorption spectroscopy experiments to study the excited-state carrier dynamics of CH3NH3PbBr3 (MAPbBr3) under hydrostatic pressure. The results indicate that compression is an effective approach to modulate the carrier dynamics of MAPbBr3. Across each pressure-induced phase, carrier relaxation, phonon scattering, and Auger recombination present different pressure-dependent properties under compression. Responsiveness is attributed to the pressure-induced variation in the lattice structure, which also changes the electronic band structure. Specifically, simultaneous prolongation of carrier relaxation and Auger recombination is achieved in the ambient phase, which is very valuable for excess energy harvesting. Our discussion provides clues for optimizing the photovoltaic performance of OTPs.

  14. FGFR2c-mediated ERK-MAPK activity regulates coronal suture development

    Science.gov (United States)

    Pfaff, Miles J.; Xue, Ke; Li, Li; Horowitz, Mark C.; Steinbacher, Derek M.; Eswarakumar, Jacob V.P.

    2017-01-01

    Fibroblast growth factor receptor 2 (FGFR2) signaling is critical for proper craniofacial development. A gain-of-function mutation in the 2c splice variant of the receptor’s gene is associated with Crouzon syndrome, which is characterized by craniosynostosis, the premature fusion of one or more of the cranial vault sutures, leading to craniofacial maldevelopment. Insight into the molecular mechanism of craniosynostosis has identified the ERK-MAPK signaling cascade as a critical regulator of suture patency. The aim of this study is to investigate the role of FGFR2c-induced ERK-MAPK activation in the regulation of coronal suture development. Loss-of-function and gain-of-function Fgfr2c mutant mice have overlapping phenotypes, including coronal synostosis and craniofacial dysmorphia. In vivo analysis of coronal sutures in loss-of-function and gain-of-function models demonstrated fundamentally different pathogenesis underlying coronal suture synostosis. Calvarial osteoblasts from gain-of-function mice demonstrated enhanced osteoblastic function and maturation with concomitant increase in ERK-MAPK activation. In vitro inhibition with the ERK protein inhibitor U0126 mitigated ERK protein activation levels with a concomitant reduction in alkaline phosphatase activity. This study identifies FGFR2c-mediated ERK-MAPK signaling as a key mediator of craniofacial growth and coronal suture development. Furthermore, our results solve the apparent paradox between loss-of-function and gain-of-function FGFR2c mutants with respect to coronal suture synostosis. PMID:27034231

  15. The origin of coronal lines in Seyfert galaxies

    International Nuclear Information System (INIS)

    Korista, K.T.; Ferland, G.J.

    1989-01-01

    This paper examines the possibility that the coronal line region in Seyfert galaxies may be the result of an interstellar medium (ISM) exposed to, and subsequently photoionized by, a 'bare' Seyfert nucleus. It is shown that a 'generic' AGN continuum illuminating the warm-phase of the ISM of a spiral galaxy can produce the observed emission. In this picture the same UV-radiation cone that is responsible for the high-excitation extended narrow-line emission clouds observed out to 1-2 kpc or farther from the nuclei of some Seyfert galaxies also produces the coronal lines. Soft X-rays originating in the nucleus are Compton-scattered off the ISM, thus producing extended soft X-ray emission, as observed in NGC 4151. The results of the calculations show a basic insensitivity to the ISM density, which explains why similar coronal line spectra are found in many Seyfert galaxies of varying physical environments. 60 refs

  16. Coronal Loop Evolution Observed with AIA and Hi-C

    Science.gov (United States)

    Mulu-Moore, Fana; Winebarger, A.; Cirtain, J.; Kobayashi, K.; Korreck, K.; Golub, L.; Kuzin. S.; Walsh, R.; DeForest, C.; DePontieu, B.; hide

    2012-01-01

    Despite much progress toward understanding the dynamics of the solar corona, the physical properties of coronal loops are not yet fully understood. Recent investigations and observations from different instruments have yielded contradictory results about the true physical properties of coronal loops. In the past, the evolution of loops has been used to infer the loop substructure. With the recent launch of High Resolution Coronal Imager (Hi-C), this inference can be validated. In this poster we discuss the first results of loop analysis comparing AIA and Hi-C data. We find signatures of cooling in a pixel selected along a loop structure in the AIA multi-filter observations. However, unlike previous studies, we find that the cooling time is much longer than the draining time. This is inconsistent with previous cooling models.

  17. Additional merit of coronal STIR imaging for MR imaging of lumbar spine

    Directory of Open Access Journals (Sweden)

    Ranjana Gupta

    2015-01-01

    Full Text Available Introduction: Back pain is a common clinical problem and is the frequent complaint for referral of lumbar spine magnetic resonance imaging (MRI. Coronal short tau inversion recovery sequence (STIR can provide diagnostically significant information in small percentage of patients. Materials and Methods: MRI examinations of a total of 350 patients were retrospectively included in the study. MR sequences were evaluated in two settings. One radiologist evaluated sagittal and axial images only, while another radiologist evaluated all sequences, including coronal STIR sequence. After recording the diagnoses, we compared the MRI findings in two subsets of patients to evaluate additional merit of coronal STIR imaging. Results: With addition of coronal STIR imaging, significant findings were observed in 24 subjects (6.8%. Twenty-one of these subjects were considered to be normal on other sequences and in three subjects diagnosis was changed with the addition of coronal STIR. Additional diagnoses on STIR included sacroiliitis, sacroiliac joint degenerative disease, sacral stress/insufficiency fracture/Looser′s zones, muscular sprain and atypical appendicitis. Conclusion: Coronal STIR imaging can provide additional diagnoses in a small percentage of patients presenting for lumbar spine MRI for back pain. Therefore, it should be included in the routine protocol for MR imaging of lumbar spine.

  18. Characterization of Final State Interaction Strength in Plastic Scintillator by Muon-Neutrino Charged Current Charged Pion Production

    Energy Technology Data Exchange (ETDEWEB)

    Eberly, Brandon M. [Univ. of Pittsburgh, PA (United States)

    2014-01-01

    Precise knowledge of neutrino-nucleus interactions is increasingly important as neutrino oscillation measurements transition into the systematics-limited era. In addition to modifying the initial interaction, the nuclear medium can scatter and absorb the interaction by-products through final state interactions, changing the types and kinematic distributions of particles seen by the detector. Recent neutrino pion production data from MiniBooNE is inconsistent with the final state interaction strength predicted by models and theoretical calculations, and some models fit best to the MiniBooNE data only after removing final state interactions entirely. This thesis presents a measurement of dσ/dTπ and dσ/dθπ for muon-neutrino charged current charged pion production in the MINER A scintillator tracker. MINER A is a neutrino-nucleus scattering experiment installed in the few-GeV NuMI beam line at Fermilab. The analysis is limited to neutrino energies between 1.5-10 GeV. Dependence on invariant hadronic mass W is studied through two versions of the analysis that impose the limits W < 1.4 GeV and W < 1.8 GeV. The lower limit on W increases compatibility with the MiniBooNE pion data. The shapes of the differential cross sections, which depend strongly on the nature of final state interactions, are compared to Monte Carlo and theoretical predictions. It is shown that the measurements presented in this thesis favor models that contain final state interactions. Additionally, a variety of neutrino-nucleus interaction models are shown to successfully reproduce the thesis measurements, while simultaneously failing to describe the shape of the MiniBooNE data.

  19. [Development of electroforming apparatus for coronal restoration].

    Science.gov (United States)

    Watanabe, M; Sawada, T; Ukiya, M

    1989-03-01

    As dental technologies become highly developed, techniques have been more diversified. From as aspect of prosthodontic practice, both esthetic and functional requirements are emphasized for coronal restoration and consequently, these should be considered in the routine procedure. In fabrication of coronal restorations, metal, porcelain and resin are commonly used, and there exists the various disadvantages for metal cast method due to complicated processes by using different dental materials. Therefore, an electroforming apparatus was developed by us to replace the conventional procedure by a cathode rotary system. It was applied for coronal restorations to allow an electroforming directly on a working model. An experiment was successfully conducted to apply for a veneer crown on abutment tooth of upper central incisor on plaster model. The results were obtained as follows, 1. It was become possible to construct a metal framework by the electroforming. 2. Metal framework can be constructed on the same working model without a duplication of it. 3. The combined system for cathode rotation and liquid circulation could shorten the electroposition time, and allows a high current density extending to 50 A/dm2.

  20. A Novel Active Online State of Charge Based Balancing Approach for Lithium-Ion Battery Packs during Fast Charging Process in Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Xiudong Cui

    2017-11-01

    Full Text Available Abstract: Non-uniformity of Lithium-ion cells in a battery pack is inevitable and has become the bottleneck to the pack capacity, especially in the fast charging process. Therefore, a balancing approach is essentially required. This paper proposes an active online cell balancing approach in a fast charging process using the state of charge (SOC as balancing criterion. The goal of this approach is to complete pack balancing within the limited charging time. An adaptive extended Kalman filter (AEKF is applied to estimate the pack cell SOC during the charging process to obtain accurate results under modeling errors and measurement noises. To implement the proposed AEKF, only one additional current sensor is required to obtain the current of each cell required for the SOC estimation. An experimental platform is established to verify the effectiveness of the proposed approach. The results show that the proposed balancing approach with the SOC as a balancing criterion can overcome the challenges of non-uniformity and flat voltage plateau and charge more capacity into a LiFePO4 battery pack than those with the terminal voltage as a balancing criterion in the fast charging process.

  1. Communicating with the Coroner: How Religion, Culture, and Family Concerns May Influence Autopsy Decision Making

    Science.gov (United States)

    Carpenter, Belinda; Tait, Gordon; Adkins, Glenda; Barnes, Michael; Naylor, Charles; Begum, Nelufa

    2011-01-01

    Based on coronial data gathered in the state of Queensland in 2004, this article reviews how a change in legislation may have impacted autopsy decision making by coroners. More specifically, the authors evaluated whether the requirement that coronial autopsy orders specify the level of invasiveness of an autopsy to be performed by a pathologist…

  2. The Coronal Analysis of SHocks and Waves (CASHeW) framework

    Science.gov (United States)

    Kozarev, Kamen A.; Davey, Alisdair; Kendrick, Alexander; Hammer, Michael; Keith, Celeste

    2017-11-01

    Coronal bright fronts (CBF) are large-scale wavelike disturbances in the solar corona, related to solar eruptions. They are observed (mostly in extreme ultraviolet (EUV) light) as transient bright fronts of finite width, propagating away from the eruption source location. Recent studies of individual solar eruptive events have used EUV observations of CBFs and metric radio type II burst observations to show the intimate connection between waves in the low corona and coronal mass ejection (CME)-driven shocks. EUV imaging with the atmospheric imaging assembly instrument on the solar dynamics observatory has proven particularly useful for detecting large-scale short-lived CBFs, which, combined with radio and in situ observations, holds great promise for early CME-driven shock characterization capability. This characterization can further be automated, and related to models of particle acceleration to produce estimates of particle fluxes in the corona and in the near Earth environment early in events. We present a framework for the coronal analysis of shocks and waves (CASHeW). It combines analysis of NASA Heliophysics System Observatory data products and relevant data-driven models, into an automated system for the characterization of off-limb coronal waves and shocks and the evaluation of their capability to accelerate solar energetic particles (SEPs). The system utilizes EUV observations and models written in the interactive data language. In addition, it leverages analysis tools from the SolarSoft package of libraries, as well as third party libraries. We have tested the CASHeW framework on a representative list of coronal bright front events. Here we present its features, as well as initial results. With this framework, we hope to contribute to the overall understanding of coronal shock waves, their importance for energetic particle acceleration, as well as to the better ability to forecast SEP events fluxes.

  3. The Fate of Cool Material in the Hot Corona: Solar Prominences and Coronal Rain

    Science.gov (United States)

    Liu, Wei; Antolin, Patrick; Sun, Xudong; Vial, Jean-Claude; Berger, Thomas

    2017-08-01

    As an important chain of the chromosphere-corona mass cycle, some of the million-degree hot coronal mass undergoes a radiative cooling instability and condenses into material at chromospheric or transition-region temperatures in two distinct forms - prominences and coronal rain (some of which eventually falls back to the chromosphere). A quiescent prominence usually consists of numerous long-lasting, filamentary downflow threads, while coronal rain consists of transient mass blobs falling at comparably higher speeds along well-defined paths. It remains puzzling why such material of similar temperatures exhibit contrasting morphologies and behaviors. We report recent SDO/AIA and IRIS observations that suggest different magnetic environments being responsible for such distinctions. Specifically, in a hybrid prominence-coronal rain complex structure, we found that the prominence material is formed and resides near magnetic null points that favor the radiative cooling process and provide possibly a high plasma-beta environment suitable for the existence of meandering prominence threads. As the cool material descends, it turns into coronal rain tied onto low-lying coronal loops in a likely low-beta environment. Such structures resemble to certain extent the so-called coronal spiders or cloud prominences, but the observations reported here provide critical new insights. We will discuss the broad physical implications of these observations for fundamental questions, such as coronal heating and beyond (e.g., in astrophysical and/or laboratory plasma environments).

  4. Anatomy-Based navigation for ventriculostomy: Nasion-coronal suture distance measurement

    Directory of Open Access Journals (Sweden)

    Mevci Özdemir

    2014-09-01

    Full Text Available Objective: In this study we aimed to determine a landmark that can be measured through the skin with nasal mid-point (bregma to coronal suture, and additionally an average value was calculated. We report, to our knowledge, the distance between the nasion-coronal sutures is reported for the first time in Turkish population. Methods: The study included 30 craniums and 30 frontal bones. Each skull from midline nasal suture to coronal suture curved up at the distance was measured with tape measure. Results: Mean values were determined. Nasal suture between coronal suture distance average 12,2 cm (min10,3 cm, up to 13,5 cm were detected. Conclusion: Nasal suture is an easily palpable area through the skin. A small incision is carried down through skin to bone at the spot 12 cm back from the nasion 3 cm lateral to the midline for ventricular drainage operation. This data provide practical information for neurosurgeon and is available everywhere. J Clin Exp Invest 2014; 5 (3: 368-370

  5. Recurring coronal holes and their rotation rates during the solar cycles 22-24

    Science.gov (United States)

    Prabhu, K.; Ravindra, B.; Hegde, Manjunath; Doddamani, Vijayakumar H.

    2018-05-01

    Coronal holes (CHs) play a significant role in making the Earth geo-magnetically active during the declining and minimum phases of the solar cycle. In this study, we analysed the evolutionary characteristics of the Recurring CHs from the year 1992 to 2016. The extended minimum of Solar Cycle 23 shows unusual characteristics in the number of persistent coronal holes in the mid- and low-latitude regions of the Sun. Carrington rotation maps of He 10830 Å and EUV 195 Å observations are used to identify the Coronal holes. The latitude distribution of the RCHs shows that most of them are appeared between ± 20° latitudes. In this period, more number of recurring coronal holes appeared in and around 100° and 200° Carrington longitudes. The large sized coronal holes lived for shorter period and they appeared close to the equator. From the area distribution over the latitude considered, it shows that more number of recurring coronal holes with area <10^{21} cm2 appeared in the southern latitude close to the equator. The rotation rates calculated from the RCHs appeared between ± 60° latitude shows rigid body characteristics. The derived rotational profiles of the coronal holes show that they have anchored to a depth well below the tachocline of the interior, and compares well with the helioseismology results.

  6. Assessment of Coronal Radiographic Parameters of the Spine in the Treatment of Adolescent Idiopathic Scoliosis.

    Science.gov (United States)

    Karami, Mohsen; Maleki, Arash; Mazda, Keyvan

    2016-10-01

    To determine the most important preoperative factors that affect postoperative coronal parameters of scoliotic curves. All Adolescent Idiopathic Scoliosis (AIS) patients included in the study were classified according to Lenke and King Classification. The fusion levels were selected according to the rigidity of the existing curves (correction less than 50%), tilt of T1 and shoulders, sagittal angle of the curves and with considering stable and neutral end vertebra. The radiographic coronal parameters: shoulders tilt angle, iliolumbar angle and coronal balance were measured in all patients before, after, and in the last follow-up visit. One hundred twenty patients after mean of 25 months follow-up (18-40 months) were included in the study. Before operation, abnormal coronal balance (more than 2 cm shift) was noticed in 46 patents (38%) and in the last visit, was noted in 22 patients (18%). Multivariate regression analysis revealed a significant predictive value of the preoperative coronal balance on the last visit coronal balance ( P value=0.01). Preoperative coronal balance is very important to make a balanced spine after surgery. Other parameters like Lenke classification or main thoracic overcorrection did not affect postoperative coronal decompensation.

  7. FAST CONTRACTION OF CORONAL LOOPS AT THE FLARE PEAK

    International Nuclear Information System (INIS)

    Liu Rui; Wang Haimin

    2010-01-01

    On 2005 September 8, a coronal loop overlying the active region NOAA 10808 was observed in TRACE 171 A to contract at ∼100 km s -1 at the peak of an X5.4-2B flare at 21:05 UT. Prior to the fast contraction, the loop underwent a much slower contraction at ∼6 km s -1 for about 8 minutes, initiating during the flare preheating phase. The sudden switch to fast contraction is presumably corresponding to the onset of the impulsive phase. The contraction resulted in the oscillation of a group of loops located below, with the period of about 10 minutes. Meanwhile, the contracting loop exhibited a similar oscillatory pattern superimposed on the dominant downward motion. We suggest that the fast contraction reflects a suddenly reduced magnetic pressure underneath due either to (1) the eruption of magnetic structures located at lower altitudes or to (2) the rapid conversion of magnetic free energy in the flare core region. Electrons accelerated in the shrinking trap formed by the contracting loop can theoretically contribute to a late-phase hard X-ray burst, which is associated with Type IV radio emission. To complement the X5.4 flare which was probably confined, a similar event observed in SOHO/EIT 195 A on 2004 July 20 in an eruptive, M8.6 flare is briefly described, in which the contraction was followed by the expansion of the same loop leading up to a halo coronal mass ejection. These observations further substantiate the conjecture of coronal implosion and suggest coronal implosion as a new exciter mechanism for coronal loop oscillations.

  8. The calculation of electron chemical potential and ion charge state and their influence on plasma conductivity in electrical explosion of metal wire

    International Nuclear Information System (INIS)

    Shi, Zongqian; Wang, Kun; Li, Yao; Shi, Yuanjie; Wu, Jian; Jia, Shenli

    2014-01-01

    The electron chemical potential and ion charge state (average ion charge and ion distribution) are important parameters in calculating plasma conductivity in electrical explosion of metal wire. In this paper, the calculating method of electron chemical potential and ion charge state is discussed at first. For the calculation of electron chemical potential, the ideal free electron gas model and Thomas-Fermi model are compared and analyzed in terms of the coupling constant of plasma. The Thomas-Fermi ionization model, which is used to calculate ion charge state, is compared with the method based on Saha equation. Furthermore, the influence of electron degenerated energy levels and ion excited states in Saha equation on the ion charge state is also analyzed. Then the influence of different calculating methods of electron chemical potential and ion charge state on plasma conductivity is discussed by applying them in the Lee-More conductivity model

  9. Formation of low charge state ions of synthetic polymers using quaternary ammonium compounds.

    Science.gov (United States)

    Nasioudis, Andreas; Joyce, William F; van Velde, Jan W; Heeren, Ron M A; van den Brink, Oscar F

    2010-07-01

    Factors such as high polymer dispersity and variation in elemental composition (of copolymers) often complicate the electrospray ionization mass spectrometry (ESI-MS) analysis of synthetic polymers with high molar mass. In the experiments described in this study, quaternary ammonium compounds were observed to facilitate the production of low charge state pseudomolecular ions when added to the spray solution for ESI-MS. This approach was then used for the ESI time-of-flight mass spectrometry (TOF-MS) analysis of synthetic polymers. Hexadecyltrimethylammonium chloride permitted the successful analysis of poly(ethylene glycol) of 2-40 kDa, poly(propylene glycol) and poly(tetramethylene glycol) oligomers. Increasing the quaternary ammonium compounds' concentration results in the production of low charge state pseudomolecular ions. A comparison of structurally different quaternary ammonium compounds showed that the best performance is expected from large molecules with specific charge localization, which leaves the charge available for interactions. The applicability of the method for the MS analysis of other polymeric systems was also studied. In the case of poly(tetramethylene glycol), the method not only shifted the distributions to higher m/z values but also allowed the detection of high molecular weight material that was not observed without addition of the modifier to the spray solution.

  10. dc Resistivity of Quantum Critical, Charge Density Wave States from Gauge-Gravity Duality.

    Science.gov (United States)

    Amoretti, Andrea; Areán, Daniel; Goutéraux, Blaise; Musso, Daniele

    2018-04-27

    In contrast to metals with weak disorder, the resistivity of weakly pinned charge density waves (CDWs) is not controlled by irrelevant processes relaxing momentum. Instead, the leading contribution is governed by incoherent, diffusive processes which do not drag momentum and can be evaluated in the clean limit. We compute analytically the dc resistivity for a family of holographic charge density wave quantum critical phases and discuss its temperature scaling. Depending on the critical exponents, the ground state can be conducting or insulating. We connect our results to dc electrical transport in underdoped cuprate high T_{c} superconductors. We conclude by speculating on the possible relevance of unstable, semilocally critical CDW states to the strange metallic region.

  11. dc Resistivity of Quantum Critical, Charge Density Wave States from Gauge-Gravity Duality

    Science.gov (United States)

    Amoretti, Andrea; Areán, Daniel; Goutéraux, Blaise; Musso, Daniele

    2018-04-01

    In contrast to metals with weak disorder, the resistivity of weakly pinned charge density waves (CDWs) is not controlled by irrelevant processes relaxing momentum. Instead, the leading contribution is governed by incoherent, diffusive processes which do not drag momentum and can be evaluated in the clean limit. We compute analytically the dc resistivity for a family of holographic charge density wave quantum critical phases and discuss its temperature scaling. Depending on the critical exponents, the ground state can be conducting or insulating. We connect our results to dc electrical transport in underdoped cuprate high Tc superconductors. We conclude by speculating on the possible relevance of unstable, semilocally critical CDW states to the strange metallic region.

  12. Attosecond Charge Migration with TDDFT: Accurate Dynamics from a Well-Defined Initial State.

    Science.gov (United States)

    Bruner, Adam; Hernandez, Samuel; Mauger, François; Abanador, Paul M; LaMaster, Daniel J; Gaarde, Mette B; Schafer, Kenneth J; Lopata, Kenneth

    2017-09-07

    We investigate the ability of time-dependent density functional theory (TDDFT) to capture attosecond valence electron dynamics resulting from sudden X-ray ionization of a core electron. In this special case the initial state can be constructed unambiguously, allowing for a simple test of the accuracy of the dynamics. The response following nitrogen K-edge ionization in nitrosobenzene shows excellent agreement with fourth-order algebraic diagrammatic construction (ADC(4)) results, suggesting that a properly chosen initial state allows TDDFT to adequately capture attosecond charge migration. Visualizing hole motion using an electron localization picture (ELF), we provide an intuitive chemical interpretation of the charge migration as a superposition of Lewis dot resonance structures.

  13. Dynamics of low density coronal plasma in low current x-pinches

    International Nuclear Information System (INIS)

    Haas, D; Bott, S C; Vikhrev, V; Eshaq, Y; Ueda, U; Zhang, T; Baranova, E; Krasheninnikov, S I; Beg, F N

    2007-01-01

    Experiments were performed on an x-pinch using a pulsed power current generator capable of producing an 80 kA current with a rise time of 50 ns. Molybdenum wires with and without gold coating were employed to study the effect of high z coating on the low-density ( 18 cm -3 ) coronal plasma dynamics. A comparison of images from XUV frames and optical probing shows that the low density coronal plasma from the wires initially converges at the mid-plane immediately above and below the cross-point. A central jet is formed which moves with a velocity of 6 x 10 4 ms -1 towards both electrodes forming a z-pinch column before the current maximum. A marked change in the low density coronal plasma dynamics was observed when molybdenum wires coated with ∼ 0.09 μm of gold were used. The processes forming the jet structure were delayed relative to bare Mo x-pinches, and the time-resolved x-ray emission also showed differences. An m = 0 instability was observed in the coronal plasma along the x-pinch legs, which were consistent with x-ray PIN diode signals in which x-ray pulses were observed before x-ray spot formation. These early time x-ray pulses were not observed with pure molybdenum x-pinches. These observations indicate that a thin layer of gold coating significantly changes the coronal plasma behaviour. Two dimensional MHD simulations were performed and qualitatively agree with experimental observations of low density coronal plasma

  14. Study of the average charge states of 188Pb and 252,254No ions at the gas-filled separator TASCA

    International Nuclear Information System (INIS)

    Khuyagbaatar, J.; Ackermann, D.; Andersson, L.-L.; Ballof, J.; Brüchle, W.; Düllmann, Ch.E.; Dvorak, J.; Eberhardt, K.; Even, J.; Gorshkov, A.; Graeger, R.; Heßberger, F.-P.; Hild, D.; Hoischen, R.; Jäger, E.; Kindler, B.

    2012-01-01

    The average charge states of 188 Pb and 252,254 No ions in dilute helium gas were measured at the gas-filled recoil separator TASCA. Hydrogen gas was also used as a filling gas for measurements of the average charge state of 254 No. Helium and hydrogen gases at pressures from 0.2 mbar to 2.0 mbar were used. A strong dependence of the average charge state on the pressure of the filling gases was observed for both, helium and hydrogen. The influence of this dependence, classically attributed to the so-called “density effect”, on the performance of TASCA was investigated. The average charge states of 254 No ions were also measured in mixtures of helium and hydrogen gases at low gas pressures around 1.0 mbar. From the experimental results simple expressions for the prediction of average charge states of heavy ions moving in rarefied helium gas, hydrogen gas, and in their mixture were derived.

  15. Tuning of tunneling current noise spectra singularities by localized states charging

    OpenAIRE

    Mantsevich, V. N.; Maslova, N. S.

    2008-01-01

    We report the results of theoretical investigations of tunneling current noise spectra in a wide range of applied bias voltage. Localized states of individual impurity atoms play an important role in tunneling current noise formation. It was found that switching "on" and "off" of Coulomb interaction of conduction electrons with two charged localized states results in power law singularity of low-frequency tunneling current noise spectrum ($1/f^{\\alpha}$) and also results on high frequency com...

  16. A contact-less method to evaluate the state of charge of nickel batteries using Foucault's eddy currents

    Science.gov (United States)

    Mancier, V.; Metrot, A.; Willmann, P.

    A nickel hydroxide electrode and a commercial battery have been studied by a new and contact-less impedance method, based on Foucault's eddy currents, with the aim of determining their state of charge. Four different current line distributions have been employed and the impedance versus time graphs obtained show a linear variation of this impedance during charge and discharge for all configurations. This new method allows the determination of the state of charge and, furthermore some "artifacts" obvious on these graphs may be useful to detect a deterioration of the studied material.

  17. Photospheric Driving of Non-Potential Coronal Magnetic Field Simulations

    Science.gov (United States)

    2016-09-19

    synthesize observable emission . In future, the computational speed of the MF model makes it a potential avenue for near- real time and/or ensemble...AFRL-AFOSR-UK-TR-2016-0030 PHOTOSPHERIC DRIVING OF NON-POTENTIAL CORONAL MAGNETIC FIELD SIMULATIONS Anthony Yeates UNIVERSITY OF DURHAM Final Report...Final 3. DATES COVERED (From - To)  15 Sep 2014 to 14 Sep 2017 4. TITLE AND SUBTITLE PHOTOSPHERIC DRIVING OF NON-POTENTIAL CORONAL MAGNETIC FIELD

  18. Reconstructing the Morphology of an Evolving Coronal Mass Ejection

    Science.gov (United States)

    2009-01-01

    694, 707 Wood, B. E., Howard, R. A ., Thernisien, A ., Plunkett, S. P., & Socker, D. G. 2009b, Sol. Phys., 259, 163 Wood, B. E., Karovska , M., Chen, J...Reconstructing the Morphology of an Evolving Coronal Mass Ejection B. E. Wood, R. A . Howard, D. G. Socker Naval Research Laboratory, Space Science...mission, we empirically reconstruct the time-dependent three-dimensional morphology of a coronal mass ejection (CME) from 2008 June 1, which exhibits

  19. Two-zone model of coronal hole structure in the high corona

    International Nuclear Information System (INIS)

    Wang, Z.; Kundu, M.R.; Yoshimura, H.

    1988-01-01

    The two-zone coronal hole structure model presently proposed for the high corona at 1.5-1.7 solar radii emerges from a comparison of computation results for the potential magnetic fields of the corona and meter-decameter radio observations. The two zones of a coronal hole are defined by the configuration of magnetic field lines around a coronal hole: (1) the central hole of an open diverging magnetic field line system; and (2) the boundary zone between the central zone of the open field line system and the closed field line system or systems surrounding the open field line system. 19 references

  20. Fermion bound states in the Kerr-Newman field with magnetic charge

    International Nuclear Information System (INIS)

    Gal'tsov, D.V.; Ershov, A.A.

    1987-01-01

    Approximate solutions of Dirac equations for 1/2 spin charged particles in the Kerr-Newman field are constructed. An equation for quasistationary states energy, taking account of their possible decay due to tunnelling in the black hole, is obtained. A problem of existence of zero modes is discussed

  1. Diagnostics of Coronal Heating in Solar Active Regions

    Science.gov (United States)

    Fludra, Andrzej; Hornsey, Christopher; Nakariakov, Valery

    2015-04-01

    We aim to develop a diagnostic method for the coronal heating mechanism in active region loops. Observational constraints on coronal heating models have been sought using measurements in the X-ray and EUV wavelengths. Statistical analysis, using EUV emission from many active regions, was done by Fludra and Ireland (2008) who studied power-law relationships between active region integrated magnetic flux and emission line intensities. A subsequent study by Fludra and Warren (2010) for the first time compared fully resolved images in an EUV spectral line of OV 63.0 nm with the photospheric magnetic field, leading to the identification of a dominant, ubiquitous variable component of the transition region EUV emission and a discovery of a steady basal heating, and deriving the dependence of the basal heating rate on the photospheric magnetic flux density. In this study, we compare models of single coronal loops with EUV observations. We assess to what degree observations of individual coronal loops made in the EUV range are capable of providing constraints on the heating mechanism. We model the coronal magnetic field in an active region using an NLFF extrapolation code applied to a photospheric vector magnetogram from SDO/HMI and select several loops that match an SDO/AIA 171 image of the same active region. We then model the plasma in these loops using a 1D hydrostatic code capable of applying an arbitrary heating rate as a function of magnetic field strength along the loop. From the plasma parameters derived from this model, we calculate the EUV emission along the loop in AIA 171 and 335 bands, and in pure spectral lines of Fe IX 17.1 nm and Fe XVI 33.5 nm. We use different spatial distributions of the heating function: concentrated near the loop top, uniform and concentrated near the footpoints, and investigate their effect on the modelled EUV intensities. We find a diagnostics based on the dependence of the total loop intensity on the shape of the heating function

  2. Defect states and charge trapping characteristics of HfO2 films for high performance nonvolatile memory applications

    International Nuclear Information System (INIS)

    Zhang, Y.; Shao, Y. Y.; Lu, X. B.; Zeng, M.; Zhang, Z.; Gao, X. S.; Zhang, X. J.; Liu, J.-M.; Dai, J. Y.

    2014-01-01

    In this work, we present significant charge trapping memory effects of the metal-hafnium oxide-SiO 2 -Si (MHOS) structure. The devices based on 800 °C annealed HfO 2 film exhibit a large memory window of ∼5.1 V under ±10 V sweeping voltages and excellent charge retention properties with only small charge loss of ∼2.6% after more than 10 4  s retention. The outstanding memory characteristics are attributed to the high density of deep defect states in HfO 2 films. We investigated the defect states in the HfO 2 films by photoluminescence and photoluminescence excitation measurements and found that the defect states distributed in deep energy levels ranging from 1.1 eV to 2.9 eV below the conduction band. Our work provides further insights for the charge trapping mechanisms of the HfO 2 based MHOS devices.

  3. DISPELLING ILLUSIONS OF REFLECTION: A NEW ANALYSIS OF THE 2007 MAY 19 CORONAL 'WAVE' EVENT

    International Nuclear Information System (INIS)

    Attrill, Gemma D. R.

    2010-01-01

    A new analysis of the 2007 May 19 coronal wave-coronal mass ejection-dimmings event is offered employing base difference extreme-ultraviolet (EUV) images. Previous work analyzing the coronal wave associated with this event concluded strongly in favor of purely an MHD wave interpretation for the expanding bright front. This conclusion was based to a significant extent on the identification of multiple reflections of the coronal wave front. The analysis presented here shows that the previously identified 'reflections' are actually optical illusions and result from a misinterpretation of the running difference EUV data. The results of this new multiwavelength analysis indicate that two coronal wave fronts actually developed during the eruption. This new analysis has implications for our understanding of diffuse coronal waves and questions the validity of the analysis and conclusions reached in previous studies.

  4. Trajectory effects in the negative charge-state fraction of 3He and 4He reflected from a sodium target

    International Nuclear Information System (INIS)

    Schneider, P.J.; Eckstein, W.; Verbeek, H.

    1984-01-01

    Measurement of the positive and negative charge-state fractions of He reflected from a sodium target with incident energies in the range of 1.75 keV/nucleon to 5 keV/nucleon are presented. The exit angle of the particles was held constant at 75 0 from the surface normal, while the incident angle was varied from 0 0 (normal incidence) to 75 0 . The positive charge-state fractions exhibited no incident-angle or incident-energy dependence and dependend only upon the exit energy. For normal incidence, the negative charge-state fractions were also only dependent upon the exit energy. However, for glancing incidence, the negative charge-state fractions were incident- and exit-energy dependent. These results are compared to previous results for D [1] and are discussed in terms of the trajectory-dependent formation probability of the negative ions. (orig.)

  5. CORONAL MASS EJECTION INDUCED OUTFLOWS OBSERVED WITH HINODE/EIS

    International Nuclear Information System (INIS)

    Jin, M.; Ding, M. D.; Chen, P. F.; Fang, C.; Imada, S.

    2009-01-01

    We investigate the outflows associated with two halo coronal mass ejections (CMEs) that occurred on 2006 December 13 and 14 in NOAA 10930, using the Hinode/EIS observations. Each CME was accompanied by an EIT wave and coronal dimmings. Dopplergrams in the dimming regions are obtained from the spectra of seven EIS lines. The results show that strong outflows are visible in the dimming regions during the CME eruption at different heights from the lower transition region to the corona. It is found that the velocity is positively correlated with the photospheric magnetic field, as well as the magnitude of the dimming. We estimate the mass loss based on height-dependent EUV dimmings and find it to be smaller than the CME mass derived from white-light observations. The mass difference is attributed partly to the uncertain atmospheric model, and partly to the transition region outflows, which refill the coronal dimmings.

  6. Projectile- and charge-state-dependent electron yields from ion penetration of solids as a probe of preequilibrium stopping power

    DEFF Research Database (Denmark)

    Rothard, H.; Schou, Jørgen; Groeneveld, K.-O.

    1992-01-01

    Kinetic electron-emission yields gamma from swift ion penetration of solids are proportional to the (electronic) stopping power gamma approximately Beta-S*, if the preequilibrium evolution of the charge and excitation states of the positively charged ions is taken into account. We show...... by investigating the "transport factor" beta, the energy spectrum of directly ejected recoil electrons and the evolution of ionic charge state inside solids. Estimates of the energy-loss fraction leading to electron emission and the effective charges of the ions near the surface allow a quantitative description...

  7. Solar Wind Charge Exchange During Geomagnetic Storms

    Science.gov (United States)

    Robertson, Ina P.; Cravens, Thomas E.; Sibeck, David G.; Collier, Michael R.; Kuntz, K. D.

    2012-01-01

    On March 31st. 2001, a coronal mass ejection pushed the subsolar magnetopause to the vicinity of geosynchronous orbit at 6.6 RE. The NASA/GSFC Community Coordinated Modeling Center (CCMe) employed a global magnetohydrodynamic (MHD) model to simulate the solar wind-magnetosphere interaction during the peak of this geomagnetic storm. Robertson et aL then modeled the expected 50ft X-ray emission due to solar wind charge exchange with geocoronal neutrals in the dayside cusp and magnetosheath. The locations of the bow shock, magnetopause and cusps were clearly evident in their simulations. Another geomagnetic storm took place on July 14, 2000 (Bastille Day). We again modeled X-ray emission due to solar wind charge exchange, but this time as observed from a moving spacecraft. This paper discusses the impact of spacecraft location on observed X-ray emission and the degree to which the locations of the bow shock and magnetopause can be detected in images.

  8. Optimal control of photovoltaic systems by a new battery state-of-charge observer

    Energy Technology Data Exchange (ETDEWEB)

    Giglioli, R; Zini, G; Conte, M; Raugi, M

    1988-06-01

    In photovoltaic power plants, the ability to accurately determine battery state-of-charge at any given time can reduce the risk of curtailed energy and allow more precise and less costly battery sizing. In this paper, a new state-of-charge observer, based on an original equivalent electric network of the lead-acid battery, is shown and used to develop an optimal control of the system. Hence, a management plan for a complete photovoltaic system is studied. Finally, a comparison between a simulation of the proposed plan and experimental data from a monitored photovoltaic plant, with very simple management requirements, is made and discussed. The present work was carried out within the framework of the Italian Finalized Energy Project-2.

  9. Coherent and Semiclassical States of a Charged Particle in a Constant Electric Field

    Science.gov (United States)

    Adorno, T. C.; Pereira, A. S.

    2018-05-01

    The method of integrals of motion is used to construct families of generalized coherent states of a nonrelativistic spinless charged particle in a constant electric field. Families of states, differing in the values of their standard deviations at the initial time, are obtained. Depending on the initial values of the standard deviations, and also on the electric field, it turns out to be possible to identify some families with semiclassical states.

  10. Diagnostics of Coronal Magnetic Fields through the Hanle Effect in UV and IR Lines

    Energy Technology Data Exchange (ETDEWEB)

    Raouafi, Nour E. [The John Hopkins University Applied Physics Laboratory, Laurel, MD (United States); Riley, Pete [Predictive Science Inc., San Diego, CA (United States); Gibson, Sarah [High Altitude Observatory, National Center for Atmospheric Research, Boulder, CO (United States); Fineschi, Silvano [The Astrophysical Observatory of Turin, National Institute for Astrophysics, Turin (Italy); Solanki, Sami K., E-mail: noureddine.raouafi@jhuapl.edu [Max-Planck-Institut für Sonnensystemforschung, Göttingen (Germany); School of Space Research, Kyung Hee University, Yongin, South (Korea, Republic of)

    2016-06-22

    The plasma thermodynamics in the solar upper atmosphere, particularly in the corona, are dominated by the magnetic field, which controls the flow and dissipation of energy. The relative lack of knowledge of the coronal vector magnetic field is a major handicap for progress in coronal physics. This makes the development of measurement methods of coronal magnetic fields a high priority in solar physics. The Hanle effect in the UV and IR spectral lines is a largely unexplored diagnostic. We use magnetohydrodynamic (MHD) simulations to study the magnitude of the signal to be expected for typical coronal magnetic fields for selected spectral lines in the UV and IR wavelength ranges, namely the H i Ly-α and the He i 10,830 Å lines. We show that the selected lines are useful for reliable diagnosis of coronal magnetic fields. The results show that the combination of polarization measurements of spectral lines with different sensitivities to the Hanle effect may be most appropriate for deducing coronal magnetic properties from future observations.

  11. Impact of Various Charge States of Hydrogen on Passivation of Dislocation in Silicon

    Science.gov (United States)

    Song, Lihui; Lou, Jingjing; Fu, Jiayi; Ji, Zhenguo

    2018-03-01

    Dislocation, one of typical crystallographic defects in silicon, is detrimental to the minority carrier lifetime of silicon wafer. Hydrogen passivation is able to reduce the recombination activity of dislocation, however, the passivation efficacy is strongly dependent on the experimental conditions. In this paper, a model based on the theory of hydrogen charge state control is proposed to explain the passivation efficacy of dislocation correlated to the peak temperature of thermal annealing and illumination intensity. Experimental results support the prediction of the model that a mix of positively charged hydrogen and negatively charged hydrogen at certain ratio can maximise the passivation efficacy of dislocation, leading to a better power conversion efficiency of silicon solar cell with dislocation in it.

  12. Future space missions and ground observatory for measurements of coronal magnetic fields

    Science.gov (United States)

    Fineschi, Silvano; Gibson, Sarah; Bemporad, Alessandro; Zhukov, Andrei; Damé, Luc; Susino, Roberto; Larruquert, Juan

    2016-07-01

    This presentation gives an overview of the near-future perspectives for probing coronal magnetism from space missions (i.e., SCORE and ASPIICS) and ground-based observatory (ESCAPE). Spectro-polarimetric imaging of coronal emission-lines in the visible-light wavelength-band provides an important diagnostics tool of the coronal magnetism. The interpretation in terms of Hanle and Zeeman effect of the line-polarization in forbidden emission-lines yields information on the direction and strength of the coronal magnetic field. As study case, this presentation will describe the Torino Coronal Magnetograph (CorMag) for the spectro-polarimetric observation of the FeXIV, 530.3 nm, forbidden emission-line. CorMag - consisting of a Liquid Crystal (LC) Lyot filter and a LC linear polarimeter. The CorMag filter is part of the ESCAPE experiment to be based at the French-Italian Concordia base in Antarctica. The linear polarization by resonance scattering of coronal permitted line-emission in the ultraviolet (UV)can be modified by magnetic fields through the Hanle effect. Space-based UV spectro-polarimeters would provide an additional tool for the disgnostics of coronal magnetism. As a case study of space-borne UV spectro-polarimeters, this presentation will describe the future upgrade of the Sounding-rocket Coronagraphic Experiment (SCORE) to include new generation, high-efficiency UV polarizer with the capability of imaging polarimetry of the HI Lyman-α, 121.6 nm. SCORE is a multi-wavelength imager for the emission-lines, HeII 30.4 nm and HI 121.6 nm, and visible-light broad-band emission of the polarized K-corona. SCORE has flown successfully in 2009. The second lauch is scheduled in 2016. Proba-3 is the other future solar mission that would provide the opportunity of diagnosing the coronal magnetic field. Proba-3 is the first precision formation-flying mission to launched in 2019). A pair of satellites will fly together maintaining a fixed configuration as a 'large rigid

  13. Mode Conversion of a Solar Extreme-ultraviolet Wave over a Coronal Cavity

    Energy Technology Data Exchange (ETDEWEB)

    Zong, Weiguo [Key Laboratory of Space Weather, National Center for Space Weather, China Meteorological Administration, Beijing 100081 (China); Dai, Yu, E-mail: ydai@nju.edu.cn [Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, Nanjing 210023 (China)

    2017-01-10

    We report on observations of an extreme-ultraviolet (EUV) wave event in the Sun on 2011 January 13 by Solar Terrestrial Relations Observatory and Solar Dynamics Observatory in quadrature. Both the trailing edge and the leading edge of the EUV wave front in the north direction are reliably traced, revealing generally compatible propagation velocities in both perspectives and a velocity ratio of about 1/3. When the wave front encounters a coronal cavity near the northern polar coronal hole, the trailing edge of the front stops while its leading edge just shows a small gap and extends over the cavity, meanwhile getting significantly decelerated but intensified. We propose that the trailing edge and the leading edge of the northward propagating wave front correspond to a non-wave coronal mass ejection component and a fast-mode magnetohydrodynamic wave component, respectively. The interaction of the fast-mode wave and the coronal cavity may involve a mode conversion process, through which part of the fast-mode wave is converted to a slow-mode wave that is trapped along the magnetic field lines. This scenario can reasonably account for the unusual behavior of the wave front over the coronal cavity.

  14. CORONAL MAGNETIC FIELDS DERIVED FROM SIMULTANEOUS MICROWAVE AND EUV OBSERVATIONS AND COMPARISON WITH THE POTENTIAL FIELD MODEL

    Energy Technology Data Exchange (ETDEWEB)

    Miyawaki, Shun; Nozawa, Satoshi [Department of Science, Ibaraki University, Mito, Ibaraki 310-8512 (Japan); Iwai, Kazumasa; Shibasaki, Kiyoto [Nobeyama Solar Radio Observatory, National Astronomical Observatory of Japan, Minamimaki, Nagano 384-1305 (Japan); Shiota, Daikou, E-mail: shunmi089@gmail.com [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya, Aichi 464-8601 (Japan)

    2016-02-10

    We estimated the accuracy of coronal magnetic fields derived from radio observations by comparing them to potential field calculations and the differential emission measure measurements using EUV observations. We derived line-of-sight components of the coronal magnetic field from polarization observations of the thermal bremsstrahlung in the NOAA active region 11150, observed around 3:00 UT on 2011 February 3 using the Nobeyama Radioheliograph at 17 GHz. Because the thermal bremsstrahlung intensity at 17 GHz includes both chromospheric and coronal components, we extracted only the coronal component by measuring the coronal emission measure in EUV observations. In addition, we derived only the radio polarization component of the corona by selecting the region of coronal loops and weak magnetic field strength in the chromosphere along the line of sight. The upper limits of the coronal longitudinal magnetic fields were determined as 100–210 G. We also calculated the coronal longitudinal magnetic fields from the potential field extrapolation using the photospheric magnetic field obtained from the Helioseismic and Magnetic Imager. However, the calculated potential fields were certainly smaller than the observed coronal longitudinal magnetic field. This discrepancy between the potential and the observed magnetic field strengths can be explained consistently by two reasons: (1) the underestimation of the coronal emission measure resulting from the limitation of the temperature range of the EUV observations, and (2) the underestimation of the coronal magnetic field resulting from the potential field assumption.

  15. Charge state distribution of 16O from the 4He(12C,16O)γ reaction of astrophysical interest studied both experimentally and theoretically

    International Nuclear Information System (INIS)

    Liu, Shengjin; Sakurai, Makoto; Sagara, Kenshi; Teranishi, Takashi; Fujita, Kunihiro; Yamaguchi, Hiroyuki; Matsuda, Sayaka; Mitsuzumi, Tatsuki; Iwazaki, Makoto; Rosary, Mariya T.; Kato, Daiji; Tolstikhina, I.Yu.

    2014-01-01

    In astrophysics, 4 He( 12 C, 16 O)γ reaction places an important role. At Kyushu University Tandem accelerator Laboratory (KUTL), the measurement of 4 He( 12 C, 16 O)γ cross section is in progress in the energy range of astrophysical nuclear reaction. Since the charge state of product 16 O ions after passing through the gas target is spread and only one charge state can be measured at terminal detector, it is necessary to know the charge state distribution of 16 O ions passing through the He gas target precisely. Here, we report the charge state distribution of the 16 O recoils both experimentally and theoretically. Experimentally, we measured the equilibrium charge state distribution of 16 O ions in the windowless helium gas target with the beam energy of primary 16 O ions at 7.2, 4.5, and 3.45 MeV at KUTL. The measured results showed a Gaussian distribution for the charge state fraction. Theoretically, we proposed a framework for the charge state distribution study. Charge state distribution was computed by solving a set of differential equations including a series of charge exchange cross sections. For the ionization cross section, plane-wave Born approximation was applied and modified by taking target atomic screening as a function of momentum transfer into account. For the capture cross section, continuum distorted wave approximation was applied and the influence of the gas target density was taken into account in the process of electron capture. Using above charge exchange cross sections, the charge state evolution was simulated. According to the equilibrium distribution, we compared the theoretical calculation to the experimental data. After taking into account the density effects in the charge exchange process, the theoretical charge state distributions shows a good agreement with the experimental data. Both experimental and theoretical results are useful to understand the charge fraction of recoil oxygen created via 4 He( 12 C, 16 O)γ reaction

  16. Solvent control of charge transfer excited state relaxation pathways in [Fe(2,2 '-bipyridine)(CN)4]2-

    DEFF Research Database (Denmark)

    Kjær, Kasper Skov; Kunnus, Kristjan; Harlang, Tobias C. B.

    2018-01-01

    The excited state dynamics of solvated [Fe(bpy)(CN)4]2-, where bpy = 2,2'-bipyridine, show significant sensitivity to the solvent Lewis acidity. Using a combination of optical absorption and X-ray emission transient spectroscopies, we have previously shown that the metal to ligand charge transfer...... the MLCT excited state relaxation dynamics of [Fe(bpy)(CN)4]2- in water, a strong Lewis acid solvent. The charge-transfer excited state is now found to decay in less than 100 femtoseconds, forming a quasi-stable metal centered excited state with a 13 picosecond lifetime. We find that this MC excited state...... developed for solar applications....

  17. Image-based reconstruction of the Newtonian dynamics of solar coronal ejecta

    Science.gov (United States)

    Uritsky, Vadim M.; Thompson, Barbara J.

    2016-10-01

    We present a new methodology for analyzing rising and falling dynamics of unstable coronal material as represented by high-cadence SDO AIA images. The technique involves an adaptive spatiotemporal tracking of propagating intensity gradients and their characterization in terms of time-evolving areas swept out by the position vector originated from the Sun disk center. The measured values of the areal velocity and acceleration are used to obtain quantitative information on the angular momentum and acceleration along the paths of the rising and falling coronal plasma. In the absence of other forces, solar gravitation results in purely ballistic motions consistent with the Kepler's second law; non-central forces such as the Lorentz force introduce non-zero torques resulting in more complex motions. The developed algorithms enable direct evaluation of the line-of-sight component of the net torque applied to a unit mass of the ejected coronal material which is proportional to the image-plane projection of the observed areal acceleration. The current implementation of the method cannot reliably distinguish torque modulations caused by the coronal force field from those imposed by abrupt changes of plasma mass density and nontrivial projection effects. However, it can provide valid observational constraints on the evolution of large-scale unstable magnetic topologies driving major solar-coronal eruptions as demonstrated in the related talk by B. Thompson et al.

  18. Molecular approaches to solar energy conversion: the energetic cost of charge separation from molecular-excited states.

    Science.gov (United States)

    Durrant, James R

    2013-08-13

    This review starts with a brief overview of the technological potential of molecular-based solar cell technologies. It then goes on to focus on the core scientific challenge associated with using molecular light-absorbing materials for solar energy conversion, namely the separation of short-lived, molecular-excited states into sufficiently long-lived, energetic, separated charges capable of generating an external photocurrent. Comparisons are made between different molecular-based solar cell technologies, with particular focus on the function of dye-sensitized photoelectrochemical solar cells as well as parallels with the function of photosynthetic reaction centres. The core theme of this review is that generating charge carriers with sufficient lifetime and a high quantum yield from molecular-excited states comes at a significant energetic cost-such that the energy stored in these charge-separated states is typically substantially less than the energy of the initially generated excited state. The role of this energetic loss in limiting the efficiency of solar energy conversion by such devices is emphasized, and strategies to minimize this energy loss are compared and contrasted.

  19. STEREO Observations of Interplanetary Coronal Mass Ejections in 2007–2016

    Science.gov (United States)

    Jian, L. K.; Russell, C. T.; Luhmann, J. G.; Galvin, A. B.

    2018-03-01

    We have conducted a survey of 341 interplanetary coronal mass ejections (ICMEs) using STEREO A/B data, analyzing their properties while extending a Level 3 product through 2016. Among the 192 ICMEs with distinguishable sheath region and magnetic obstacle, the magnetic field maxima in the two regions are comparable, and the dynamic pressure peaks mostly in the sheath. The north/south direction of the magnetic field does not present any clear relationship between the sheath region and the magnetic obstacle. About 71% of ICMEs are expanding at 1 au, and their expansion speed varies roughly linearly with their maximum speed except for ICMEs faster than 700 km s‑1. The total pressure generally peaks near the middle of the well-defined magnetic cloud (MC) passage, while it often declines along with the non-MC ICME passage, consistent with our previous interpretation concerning the effects of sampling geometry on what is observed. The hourly average iron charge state reaches above 12+ ∼31% of the time for MCs, ∼16% of the time for non-MC ICMEs, and ∼1% of the time for non-ICME solar wind. In four ICMEs abrupt deviations of the magnetic field from the nominal field rotations occur in the magnetic obstacles, coincident with a brief drop or increase in field strength—features could be related to the interaction with dust. In comparison with the similar phases of solar cycle 23, the STEREO ICMEs in this cycle occur less often and are generally weaker and slower, although their field and pressure compressions weaken less than the background solar wind.

  20. Spectroscopic observations of Nova Cygni 1975: The coronal line region revisited

    International Nuclear Information System (INIS)

    Ferland, G.J.; Lambert, D.L.; Woodman, J.H.

    1986-01-01

    A synopsis of the McDonald Observatory spectrophotometric observations of Nova Cyg 1975 (V1500 Cyg) is presented. We present these data in a form in which they can be readily accessed in the future, and also study the continous spectrum during the early nebular phase. We show that (1) the remnant probably maintained a luminosity at or above the Eddington limit for at least a year after outburst, (2) free-free emission from the coronal line region made a significant contribution to the optical continuum, and (3) the coronal line region was probably a significant source of ionizing radiation. The energetics of this nova appear to be dominated by the lift-off energy from the white dwarf and radiation from the coronal line region. Thus the light curve of Nova Cyg may tell more about the cooling of the coronal line region than about the decline of the central object. In appendices we discuss the argon abundance of Nova Cyg (less than 8 times solar) and describe how to obtain copies of the McDonald nova data

  1. Charge exchange cross-sections for multiply charged ions

    International Nuclear Information System (INIS)

    Midha, J.M.; Gupta, S.C.

    1990-01-01

    A new empirical relation for charge exchange cross-section has been proposed for different charge states of C, N and O colliding with neutral hydrogen. Results are compared with the experimental data. (Author)

  2. Effect of charged and excited states on the decomposition of 1,1-diamino-2,2-dinitroethylene molecules

    International Nuclear Information System (INIS)

    Kimmel, Anna V.; Sushko, Peter V.; Shluger, Alexander L.; Kuklja, Maija M.

    2007-01-01

    The authors have calculated the electronic structure of individual 1,1-diamino-2,2-dinitroethylene molecules (FOX-7) in the gas phase by means of density functional theory with the hybrid B3LYP functional and 6-31+G(d,p) basis set and considered their dissociation pathways. Positively and negatively charged states as well as the lowest excited states of the molecule were simulated. They found that charging and excitation can not only reduce the activation barriers for decomposition reactions but also change the dominating chemistry from endo- to exothermic type. In particular, they found that there are two competing primary initiation mechanisms of FOX-7 decomposition: C-NO 2 bond fission and C-NO 2 to CONO isomerization. Electronic excitation or charging of FOX-7 disfavors CONO formation and, thus, terminates this channel of decomposition. However, if CONO is formed from the neutral FOX-7 molecule, charge trapping and/or excitation results in spontaneous splitting of an NO group accompanied by the energy release. Intramolecular hydrogen transfer is found to be a rare event in FOX-7 unless free electrons are available in the vicinity of the molecule, in which case HONO formation is a feasible exothermic reaction with a relatively low energy barrier. The effect of charged and excited states on other possible reactions is also studied. Implications of the obtained results to FOX-7 decomposition in condensed state are discussed

  3. Added value of using a CT coronal reformation to diagnose adnexal torsion

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Sung Il; Park, Hee Sun; Yim, Young Hee; Jeon, Hae Jeong; Yu, Mi Hye; Kim, Young Jun [Dept. of Radiology, Konkuk University School of Medicine, Research Institute of Medical Science, Seoul (Korea, Republic of); Jeong, Kyung Ah [Dept. of Obstetrics and Gynecology, School of Medicine, Ewha Womans University, Seoul (Korea, Republic of)

    2015-08-15

    To evaluate the increased value of using coronal reformation of a transverse computed tomography (CT) scan for detecting adnexal torsion. This study included 106 woman suspected of having adnexal torsion who underwent CT with coronal reformations and subsequent surgical exploration. Two readers independently recorded the CT findings, such as the thickening of a fallopian tube, twisting of the adnexal pedicle, eccentric smooth wall thickening of the torsed adnexal mass, eccentric septal thickening of the torsed adnexal mass, eccentric poor enhancement of the torsed adnexal mass, uterine deviation to the twisted side, ascites or infiltration of pelvic fat, and the overall impression of adnexal torsion with a transverse scan alone or combined with coronal reformation and a transverse scan. The areas under the receiver operating characteristic curves (AUCs), sensitivity, specificity, and positive predictive value were used to compare diagnostic performance. Fifty-two patients were confirmed to have adnexal torsion. The addition of coronal reformations to the transverse scan improved AUCs for readers 1 and 2 from 0.74 and 0.75 to 0.92 and 0.87, respectively, for detecting adnexal torsion (p < 0.001 and p = 0.004, respectively). Sensitivity of CT for detecting twisting of the adnexal pedicle increased significantly for readers 1 and 2 from 0.27 and 0.29 with a transverse scan alone to 0.79 and 0.77 with a combined coronal reformation and a transverse scan, respectively (p < 0.001 and p < 0.001, respectively). Use of a coronal reformation with transverse CT images improves detection of adnexal torsion.

  4. Swift X-ray monitoring of stellar coronal variability

    Science.gov (United States)

    Miller, Brendan; Hagen, Cedric; Gallo, Elena; Wright, Jason T.

    2018-01-01

    We used California Planet Search Ca II H and K core emission measurements to identify and characterize chromospheric activity cycles in a sample of main-sequence FGK stars. About a dozen of these with existing ROSAT archival data were targeted with Swift to obtain a current epoch X-ray flux. We find that coronal variability by a factor of several is common on decade-long timescales (we attempt to link to the chromospheric cycle phase) but can also occur on short timescales between Swift visits to a given target, presumably related to stellar rotation and coronal inhomogeneity or to small flares. Additionally, we present new Swift monitoring observations of two M dwarfs with known exoplanets: GJ 15A and GJ 674. GJ 15A b is around 5.3 Earth masses with an 11.4 day orbital period, while GJ 674 is around 11.1 Earth masses with a 4.7 day orbital period. GJ 15A was observed several times in late 2014 and then monitored at approximately weekly intervals for several months in early 2016, for a total exposure of 18 ks. GJ 674 was monitored at approximately weekly intervals for most of 2016, for a total exposure of 40 ks. We provide light curves and hardness ratios for both sources, and also compare to earlier archival X-ray data. Both sources show significant X-ray variability, including between consecutive observations. We quantify the energy distribution for coronal flaring, and compare to optical results for M dwarfs from Kepler. Finally, we discuss the implications of M dwarf coronal activity for exoplanets orbiting within the nominal habitable zone.

  5. The average equilibrium charge-states of heavy ions with Z > 60 stripped in He and H2

    International Nuclear Information System (INIS)

    Oganessian, Yu.T.; Lobanov, Yu.V.; Popeko, A.G.; Abdullin, F.Sh.; Kharitonov, Yu.P.; Ledovskoy, A.A.; Tsyganov, Yu.S.

    1991-01-01

    The equilibrium charges of heavy ions (61 < Z < 101) with energies from 5 to 100 MeV stripped in He and H2 have been measured. New empirical formulae for the average charge state are presented. (orig.)

  6. Does Tibial Slope Affect Perception of Coronal Alignment on a Standing Anteroposterior Radiograph?

    Science.gov (United States)

    Schwartz, Adam J; Ravi, Bheeshma; Kransdorf, Mark J; Clarke, Henry D

    2017-07-01

    A standing anteroposterior (AP) radiograph is commonly used to evaluate coronal alignment following total knee arthroplasty (TKA). The impact of coronal alignment on TKA outcomes is controversial, perhaps due to variability in imaging and/or measurement technique. We sought to quantify the effect of image rotation and tibial slope on coronal alignment. Using a standard extramedullary tibial alignment guide, 3 cadaver legs were cut to accept a tibial tray at 0°, 3°, and 7° of slope. A computed tomography scan of the entire tibia was obtained for each specimen to confirm neutral coronal alignment. Images were then obtained at progressive 10° intervals of internal and external rotation up to 40° maximum in each direction. Images were then randomized and 5 blinded TKA surgeons were asked to determine coronal alignment. Continuous data values were transformed to categorical data (neutral [0], valgus [L], and varus [R]). Each 10° interval of external rotation of a 7° sloped tibial cut (or relative internal rotation of a tibial component viewed in the AP plane) resulted in perception of an additional 0.75° of varus. The slope of the proximal tibia bone cut should be taken into account when measuring coronal alignment on a standing AP radiograph. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Do coronal holes influence cosmic ray daily harmonics

    International Nuclear Information System (INIS)

    Ahluwalia, H.S.

    1977-01-01

    Coronal holes are identified by their low emissivity in either EUV (Munro and Withrobe, 1973) or in X-rays (Krieger et al, 1973). They are seats of unidirectional magnetic fields. Also, high speed solar wind streams originate in them. Also, high speed solar wind streams originate in then (Krieger et al, 1973; Neupert and Pizzo, 1974; Nolte et al, 1976). Coronal holes often extend over a wide range of heliolatitudes (Timothy et al, 1975). Elsewhere in the Proceedings we have presented results on the long term changes observed in the amplitudes and the times of maximum of the diurnal, the semidiurnal and the tridiurnal variations of cosmic rays, at low (neutrons) and at high (underground muons) primary rigidities (Ahluwalia, 1977). We have shown that a dramatic shift to early hours is noticeable in the times of maxima of the harmonics during 1971-72 period. In this paper we examine the nature of the contributions of off-ecliptic cosmic rays of high enough rigidity, streaming under the influence of large scale ordered interplanetary magnetic field set up by the coronal holes, to the cosmic ray daily harmonics. Some models are presented and discussed in a preliminary fashion. (author)

  8. Coronal Physics and the Chandra Emission Line Project

    Science.gov (United States)

    Brickhouse, N. S.; Drake, J. J.

    2000-01-01

    With the launch of the Chandra X-ray Observatory, high resolution X-ray spectroscopy of cosmic sources has begun. Early, deep observations of three stellar coronal sources Capella, Procyon, and HR 1099 are providing not only invaluable calibration data, but also benchmarks for plasma spectral models. These models are needed to interpret data from stellar coronae, galaxies and clusters of galaxies, supernova, remnants and other astrophysical sources. They have been called into question in recent years as problems with understanding low resolution ASCA and moderate resolution Extreme Ultraviolet Explorer Satellite (EUVE) data have arisen. The Emission Line Project is a collaborative effort, to improve the models, with Phase I being the comparison of models with observed spectra of Capella, Procyon, and HR 1099. Goals of these comparisons are (1) to determine and verify accurate and robust diagnostics and (2) to identify and prioritize issues in fundamental spectroscopy which will require further theoretical and/or laboratory work. A critical issue in exploiting the coronal data for these purposes is to understand the extent, to which common simplifying assumptions (coronal equilibrium, negligible optical depth) apply. We will discuss recent, advances in our understanding of stellar coronae, in this context.

  9. Adaptive Kalman filter based state of charge estimation algorithm for lithium-ion battery

    International Nuclear Information System (INIS)

    Zheng Hong; Liu Xu; Wei Min

    2015-01-01

    In order to improve the accuracy of the battery state of charge (SOC) estimation, in this paper we take a lithium-ion battery as an example to study the adaptive Kalman filter based SOC estimation algorithm. Firstly, the second-order battery system model is introduced. Meanwhile, the temperature and charge rate are introduced into the model. Then, the temperature and the charge rate are adopted to estimate the battery SOC, with the help of the parameters of an adaptive Kalman filter based estimation algorithm model. Afterwards, it is verified by the numerical simulation that in the ideal case, the accuracy of SOC estimation can be enhanced by adding two elements, namely, the temperature and charge rate. Finally, the actual road conditions are simulated with ADVISOR, and the simulation results show that the proposed method improves the accuracy of battery SOC estimation under actual road conditions. Thus, its application scope in engineering is greatly expanded. (paper)

  10. THE CORONAL ABUNDANCE ANOMALIES OF M DWARFS

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Brian E.; Laming, J. Martin [Naval Research Laboratory, Space Science Division, Washington, DC 20375 (United States); Karovska, Margarita, E-mail: brian.wood@nrl.navy.mil [Smithsonian Astrophysical Observatory, 60 Garden St., Cambridge, MA 02138 (United States)

    2012-07-01

    We analyze Chandra X-ray spectra of the M0 V+M0 V binary GJ 338. As quantified by X-ray surface flux, these are the most inactive M dwarfs ever observed with X-ray grating spectroscopy. We focus on measuring coronal abundances, in particular searching for evidence of abundance anomalies related to first ionization potential (FIP). In the solar corona and wind, low-FIP elements are overabundant, which is the so-called FIP effect. For other stars, particularly very active ones, an 'inverse FIP effect' is often observed, with low-FIP elements being underabundant. For both members of the GJ 338 binary, we find evidence for a modest inverse FIP effect, consistent with expectations from a previously reported correlation between spectral type and FIP bias. This amounts to strong evidence that all M dwarfs should exhibit the inverse FIP effect phenomenon, not just the active ones. We take the first step toward modeling the inverse FIP phenomenon in M dwarfs, building on past work that has demonstrated that MHD waves coursing through coronal loops can lead to a ponderomotive force that fractionates elements in a manner consistent with the FIP effect. We demonstrate that in certain circumstances this model can also lead to an inverse FIP effect, pointing the way to more detailed modeling of M dwarf coronal abundances in the future.

  11. The Coronal Abundance Anomalies of M Dwarfs

    Science.gov (United States)

    Wood, Brian E.; Laming, J. Martin; Karovska, Margarita

    2012-07-01

    We analyze Chandra X-ray spectra of the M0 V+M0 V binary GJ 338. As quantified by X-ray surface flux, these are the most inactive M dwarfs ever observed with X-ray grating spectroscopy. We focus on measuring coronal abundances, in particular searching for evidence of abundance anomalies related to first ionization potential (FIP). In the solar corona and wind, low-FIP elements are overabundant, which is the so-called FIP effect. For other stars, particularly very active ones, an "inverse FIP effect" is often observed, with low-FIP elements being underabundant. For both members of the GJ 338 binary, we find evidence for a modest inverse FIP effect, consistent with expectations from a previously reported correlation between spectral type and FIP bias. This amounts to strong evidence that all M dwarfs should exhibit the inverse FIP effect phenomenon, not just the active ones. We take the first step toward modeling the inverse FIP phenomenon in M dwarfs, building on past work that has demonstrated that MHD waves coursing through coronal loops can lead to a ponderomotive force that fractionates elements in a manner consistent with the FIP effect. We demonstrate that in certain circumstances this model can also lead to an inverse FIP effect, pointing the way to more detailed modeling of M dwarf coronal abundances in the future.

  12. THE CORONAL ABUNDANCE ANOMALIES OF M DWARFS

    International Nuclear Information System (INIS)

    Wood, Brian E.; Laming, J. Martin; Karovska, Margarita

    2012-01-01

    We analyze Chandra X-ray spectra of the M0 V+M0 V binary GJ 338. As quantified by X-ray surface flux, these are the most inactive M dwarfs ever observed with X-ray grating spectroscopy. We focus on measuring coronal abundances, in particular searching for evidence of abundance anomalies related to first ionization potential (FIP). In the solar corona and wind, low-FIP elements are overabundant, which is the so-called FIP effect. For other stars, particularly very active ones, an 'inverse FIP effect' is often observed, with low-FIP elements being underabundant. For both members of the GJ 338 binary, we find evidence for a modest inverse FIP effect, consistent with expectations from a previously reported correlation between spectral type and FIP bias. This amounts to strong evidence that all M dwarfs should exhibit the inverse FIP effect phenomenon, not just the active ones. We take the first step toward modeling the inverse FIP phenomenon in M dwarfs, building on past work that has demonstrated that MHD waves coursing through coronal loops can lead to a ponderomotive force that fractionates elements in a manner consistent with the FIP effect. We demonstrate that in certain circumstances this model can also lead to an inverse FIP effect, pointing the way to more detailed modeling of M dwarf coronal abundances in the future.

  13. Automated Identification of Coronal Holes from Synoptic EUV Maps

    Science.gov (United States)

    Hamada, Amr; Asikainen, Timo; Virtanen, Ilpo; Mursula, Kalevi

    2018-04-01

    Coronal holes (CHs) are regions of open magnetic field lines in the solar corona and the source of the fast solar wind. Understanding the evolution of coronal holes is critical for solar magnetism as well as for accurate space weather forecasts. We study the extreme ultraviolet (EUV) synoptic maps at three wavelengths (195 Å/193 Å, 171 Å and 304 Å) measured by the Solar and Heliospheric Observatory/Extreme Ultraviolet Imaging Telescope (SOHO/EIT) and the Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA) instruments. The two datasets are first homogenized by scaling the SDO/AIA data to the SOHO/EIT level by means of histogram equalization. We then develop a novel automated method to identify CHs from these homogenized maps by determining the intensity threshold of CH regions separately for each synoptic map. This is done by identifying the best location and size of an image segment, which optimally contains portions of coronal holes and the surrounding quiet Sun allowing us to detect the momentary intensity threshold. Our method is thus able to adjust itself to the changing scale size of coronal holes and to temporally varying intensities. To make full use of the information in the three wavelengths we construct a composite CH distribution, which is more robust than distributions based on one wavelength. Using the composite CH dataset we discuss the temporal evolution of CHs during the Solar Cycles 23 and 24.

  14. Triphenylene columnar liquid crystals: spectroscopic study of triplets states and charge carriers

    International Nuclear Information System (INIS)

    Bondkowski, Jens

    2000-01-01

    This research thesis reports the study of three oxygenated derivatives of triphenylene (two monomers, a symmetric one and an asymmetric one, and a tetramer) by using different experimental techniques: absorption spectroscopy and fluorescence spectroscopy in stationary regime, and time-resolved fluorescence spectroscopy (also said single photon counting). Moreover, the author adapted an existing experiment of transient absorption spectroscopy time-resolved at the microsecond level to obtain spectra of thin layers under electric field. A cyclic voltammetry experiment and a spectro-electrochemistry experiment have also been performed. The report first presents the studied materials, the characterisation of singlet states, and the study of the effect molecular symmetry decreasing have on molecular transitions. Then, the author reports the study of cationic species of the triphenylene derivatives. The next chapters address the characterisation of derivative triplet states, and the study of energy transfer within the meso phase of one of these derivatives. The last chapters address charge carriers of columnar liquid crystals, and the molecular nature of these charge carriers

  15. Charge state and slowing of fast ions in a plasma

    International Nuclear Information System (INIS)

    Nardi, E.; Zinamon, Z.

    1982-01-01

    The charge state of a projectile ion traveling through a plasma target under conditions relevant to ion-beam fusion is calculated. It is found that, at the projectile energies and target parameters considered, the projectile ionization is significantly higher than that of the same projectile species in a cold target. The resulting strong effects on the range and on the shape of the energy deposition profile are shown in several examples of full dynamic calculations

  16. A SURVEY OF CORONAL CAVITY DENSITY PROFILES

    International Nuclear Information System (INIS)

    Fuller, J.; Gibson, S. E.

    2009-01-01

    Coronal cavities are common features of the solar corona that appear as darkened regions at the base of coronal helmet streamers in coronagraph images. Their darkened appearance indicates that they are regions of lowered density embedded within the comparatively higher density helmet streamer. Despite interfering projection effects of the surrounding helmet streamer (which we refer to as the cavity rim), Fuller et al. have shown that under certain conditions it is possible to use a Van de Hulst inversion of white-light polarized brightness (pB) data to calculate the electron density of both the cavity and cavity rim plasma. In this article, we apply minor modifications to the methods of Fuller et al. in order to improve the accuracy and versatility of the inversion process, and use the new methods to calculate density profiles for both the cavity and cavity rim in 24 cavity systems. We also examine trends in cavity morphology and how departures from the model geometry affect our density calculations. The density calculations reveal that in all 24 cases the cavity plasma has a flatter density profile than the plasma of the cavity rim, meaning that the cavity has a larger density depletion at low altitudes than it does at high altitudes. We find that the mean cavity density is over four times greater than that of a coronal hole at an altitude of 1.2 R sun and that every cavity in the sample is over twice as dense as a coronal hole at this altitude. Furthermore, we find that different cavity systems near solar maximum span a greater range in density at 1.2 R sun than do cavity systems near solar minimum, with a slight trend toward higher densities for systems nearer to solar maximum. Finally, we found no significant correlation of cavity density properties with cavity height-indeed, cavities show remarkably similar density depletions-except for the two smallest cavities that show significantly greater depletion.

  17. A charged 3P superfluid in the ABM states

    International Nuclear Information System (INIS)

    Ohmi, Tetsuo; Nakahara, Mikio; Tsuneto, Toshihiko

    1980-01-01

    Magnetic properties of a charged 3 P superfluid in the ABM states are studied in the framework of the Ginzburg-Landau theory. A non-singular vortex in a cylindrical sample, similar to the Mermin-Ho structure in the superfluid 3 He-A, is considered. In particular, the analytic solutions for the order parameter and the magnetic field are obtained in the limit lambda sub(L)/R → 0, where lambda sub(L) is the penetration depth and R the radius of the cylinder. The possibility of a non-singular vortex lattice is also discussed. (author)

  18. MHD aspects of coronal transients

    International Nuclear Information System (INIS)

    Anzer, U.

    1979-10-01

    If one defines coronal transients as events which occur in the solar corona on rapid time scales (< approx. several hours) then one would have to include a large variety of solar phenomena: flares, sprays, erupting prominences, X-ray transients, white light transients, etc. Here we shall focus our attention on the latter two phenomena. (orig.) 891 WL/orig. 892 RDG

  19. Cross sections for charge change in argon and equilibrium charge states of 3.5 MeV/amu uranium ions passing through argon and carbon targets

    International Nuclear Information System (INIS)

    Perumal, A.N.; Horvat, V.; Watson, R.L.; Peng, Y.; Fruchey, K.S.

    2005-01-01

    Cross sections for single and multiple electron capture and loss were measured for 3.5 MeV/amu uranium ions, traveling in argon gas, as a function of incident charge state. Multiple electron loss in single collisions was found to contribute significantly to the total loss cross section. The measured cross sections were used to determine the average equilibrium charge in argon by three different methods. The resulting charges were in good agreement with each other and with the effective charge calculated from stopping powers. In order to investigate the gas-solid (density) effect on the average equilibrium charge, the charge distributions of 3.5 MeV/amu uranium ions emerging from carbon foils of different thicknesses were measured. It was found that the average equilibrium charge of the uranium ions emerging from the solid is 41% larger than that of the uranium ions emerging from the gas. The energy dependences of the average equilibrium charges for uranium ions exiting carbon and argon targets were examined by combining the present results with previous results of other investigators and compared with the predictions of a semiempirical formula developed recently by Schiwietz and Grande

  20. Quark charge retention in final state hadrons form deep inelastic muon scattering

    International Nuclear Information System (INIS)

    Albanese, J.P.; Blum, D.; Heusse, P.; Jaffre, M.; Jacholkowska, A.; Pascaud, C.; Carr, J.; Chima, J.S.; Clifft, R.; Edwards, M.; Norton, P.R.; Oakham, F.G.; Thompson, J.C.; Figiel, J.; Hoppe, C.; Janata, F.; Preissner, H.; Rondio, E.; Studt, M.; La Torre, A. de; Dengler, F.; Derado, I.; Eckardt, V.; Manz, A.; Schmitz, N.; Shiers, J.; Wolf, G.; Arneodo, M.; Arvidson, A.; Aubert, J.J.; Becks, K.H.; Bee, C.; Benchouk, C.; Bird, I.; Boehm, E.; Braun, H.; Brown, S.; Brueck, H.; Calen, H.; Callebaut, D.; Cobb, J.H.; Combley, F.; Coughlan, J.; Court, G.R.; D'Agostini, G.; Dahlgren, S.; Davies, J.K.; Dau, W.D.; Dreyer, T.; Drees, J.; Dumont, J.J.; Dueren, M.; Edwards, A.; Ernst, T.; Ferrero, M.I.; Foster, J.; Gamet, R.; Geddes, N.; Giubellino, P.; Grafstroem, P.; Grard, F.; Gustafsson, L.; Haas, J.; Hagberg, E.; Hasert, F.J.; Hayman, P.; Johnson, A.S.; Kabuss, E.M.; Krueger, J.; Kullander, S.; Landgraf, U.; Lanske, D.; Loken, J.; Long, K.; Mohr, W.; Montanet, F.; Mount, R.P.; Paul, L.; Payre, P.; Peroni, C.; Pettingale, J.; Poetsch, M.; Renton, P.; Rith, K.; Schlagboehmer, A.; Schroeder, T.; Schultze, K.; Sloan, T.; Stier, H.E.; Stockhausen, W.; Taylor, G.; Wahlen, H.; Wallucks, W.; Whalley, M.; Williams, W.S.C.; Wheeler, S.; Wimpenny, S.; Windmolders, R.

    1984-01-01

    The net charge of final state hadrons in both the current and target fragmentation regions has been measured in a 280 GeV/c muon-proton scattering experiment. A clean kinematic separation of the two regions in the centre-of-mass rapidity is demonstrated. The dependence on chisub(Bj) of the mean net charges is found to be consistent with a large contribution of sea quarks at small chisub(Bj) and with the dominance of valence quarks at large chisub(Bj) thus giving clear confirmation of the quark-parton model. It is also shown that the leading forward hadron has a high probability of containing the struck quark. (orig.)

  1. Why fast solar wind originates from slowly expanding coronal flux tubes

    International Nuclear Information System (INIS)

    Wang, Y.M.; Sheeley, N.R. Jr.

    1991-01-01

    Empirical studies indicate that the solar wind speed at earth is inversely correlated with the divergence rate of the coronal magnetic field. It is shown that this result is consistent with simple wind acceleration models involving Alfven waves, provided that the wave energy flux at the coronal base is taken to be roughly constant within open field regions. 9 refs

  2. Mechanisms of charge-state determination in hydrogen-based impurity complexes in crystalline germanium

    International Nuclear Information System (INIS)

    Oliva, J.

    1984-01-01

    Recent experiments suggest that hydrogen may become bound to, and then tunnel around, substitutional carbon, silicon, or oxygen impurities in crystalline germanium. All these complexes are electrically active; [H,C] and [H,Si] are shallow acceptors, while [H,O] is a shallow donor. This paper attempts to elucidate the basic physical mechanisms controlling the charge state of such complexes as a function of the choice of the substitutional atom. A minimal-basis Bethe-cluster approach is used with the cluster comprising the ten-atom tetrahedral cage (including the substitutional atom) and enclosed H site, the latter coupled to all ten atoms of the cage. The important local correlation effect which tends to favor single occupation of the H site is modeled with a Hubbard-type term at that site. The charge state of the [H,C], [H,Si], and [H,O] complexes is associated with double occupation of the H site. Four aspects of the model are involved in favoring double occupation: (1) a low value of the H-site energy, (2) a reduced local correlation effect at the H site, (3) small hybridization between the H site and cage, and (4) a low value of the substitutional-site energy relative to that of the host. Results for the charge state for H at the cage center and for H near the substitutional atom are discussed in detail. Several useful formal results for local self-energies and local Green's functions are presented

  3. Trap-controlled charge transport in corona-charged Teflon

    International Nuclear Information System (INIS)

    Gross, B.; Giacometti, J.A.; Ferreira, G.F.L.; Moreno A, R.A.

    1980-01-01

    The stability of negatively charged Teflon electrets is discussed. It is stated that it can only be explained by the assumption that the transport of excess charge is trap - controlled rather than mobility - controlled. (I.C.R.) [pt

  4. Modeling and state-of-charge prediction of lithium-ion battery and ultracapacitor hybrids with a co-estimator

    International Nuclear Information System (INIS)

    Wang, Yujie; Liu, Chang; Pan, Rui; Chen, Zonghai

    2017-01-01

    The modeling and state-of-charge estimation of the batteries and ultracapacitors are crucial to the battery/ultracapacitor hybrid energy storage system. In recent years, the model based state estimators are welcomed widely, since they can adjust the gain according to the error between the model predictions and measurements timely. In most of the existing algorithms, the model parameters are either configured by theoretical values or identified off-line without adaption. But in fact, the model parameters always change continuously with loading wave or self-aging, and the lack of adaption will reduce the estimation accuracy significantly. To overcome this drawback, a novel co-estimator is proposed to estimate the model parameters and state-of-charge simultaneously. The extended Kalman filter is employed for parameter updating. To reduce the convergence time, the recursive least square algorithm and the off-line identification method are used to provide initial values with small deviation. The unscented Kalman filter is employed for the state-of-charge estimation. Because the unscented Kalman filter takes not only the measurement uncertainties but also the process uncertainties into account, it is robust to the noise. Experiments are executed to explore the robustness, stability and precision of the proposed method. - Highlights: • A co-estimator is proposed to estimate the model parameters and state-of-charge. • The extended Kalman filter is used for model parameter adaption. • The unscented Kalman filter is designed for state estimation with strong robust. • The dynamic profiles are employed to verify the proposed co-estimator.

  5. The evolution of ion charge states in cathodic vacuum arc plasmas: a review

    Energy Technology Data Exchange (ETDEWEB)

    Anders, Andre

    2011-12-18

    Cathodic vacuum arc plasmas are known to contain multiply charged ions. 20 years after “Pressure Ionization: its role in metal vapour vacuum arc plasmas and ion sources” appeared in vol. 1 of Plasma Sources Science and Technology, it is a great opportunity to re-visit the issue of pressure ionization, a non-ideal plasma effect, and put it in perspective to the many other factors that influence observable charge state distributions, such as the role of the cathode material, the path in the density-temperature phase diagram, the “noise” in vacuum arc plasma as described by a fractal model approach, the effects of external magnetic fields and charge exchange collisions with neutrals. A much more complex image of the vacuum arc plasma emerges putting decades of experimentation and modeling in perspective.

  6. Photoinduced ultrafast charge-order melting: Charge-order inversion and nonthermal effects

    International Nuclear Information System (INIS)

    Veenendaal, Michel van

    2016-01-01

    The effect of photoexcitation is studied for a system with checkerboard charge order induced by displacements of ligands around a metal site. The motion of the ligands is treated classically and the electronic charges are simplified to two-level molecular bond charges. The calculations are done for a checkerboard charge-ordered system with about 100 000 ligand oscillators coupled to a fixed-temperature bath. The initial photoexcitation is followed by a rapid decrease in the charge-order parameter within 50–100 femtoseconds while leaving the correlation length almost unchanged. Depending on the fluence, a complete melting of the charge order occurs in less than a picosecond. While for low fluences, the system returns to its original state, for full melting, it recovers to its broken-symmetry state leading to an inversion of the charge order. Finally, for small long-range interactions, recovery can be slow due to domain formation.

  7. Relationship between coronal holes and high speed streams at L1: arrival times, durations, and intensities

    Science.gov (United States)

    Luo, B.; Bu, X.; Liu, S.; Gong, J.

    2017-12-01

    Coronal holes are sources of high-speed steams (HSS) of solar wind. When coronal holes appear at mid/low latitudes on the Sun, consequential HSSs may impact Earth and cause recurrent geospace environment disturbances, such as geomagnetic storms, relativistic electron enhancements at the geosynchronous orbit, and thermosphere density enhancements. Thus, it is of interests for space weather forecasters to predict when (arrival times), how long (time durations), and how severe (intensities) HSSs may impact Earth when they notice coronal holes on the sun and are anticipating their geoeffectiveness. In this study, relationship between coronal holes and high speed streams will be statistically investigated. Several coronal hole parameters, including passage times of solar central meridian, coronal hole longitudinal widths, intensities reflected by mean brightness, are derived using Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) images for years 2011 to 2016. These parameters will be correlated with in-situ solar wind measurements measured at the L1 point by the ACE spacecraft, which can give some results that are useful for space weather forecaster in predicting the arrival times, durations, and intensities of coronal hole high-speed streams in about 3 days advance.

  8. Influence of coronal holes on CMEs in causing SEP events

    International Nuclear Information System (INIS)

    Shen Chenglong; Yao Jia; Wang Yuming; Ye Pinzhong; Wang Shui; Zhao Xuepu

    2010-01-01

    The issue of the influence of coronal holes (CHs) on coronal mass ejections (CMEs) in causing solar energetic particle (SEP) events is revisited. It is a continuation and extension of our previous work, in which no evident effects of CHs on CMEs in generating SEPs were found by statistically investigating 56 CME events. This result is consistent with the conclusion obtained by Kahler in 2004. We extrapolate the coronal magnetic field, define CHs as the regions consisting of only open magnetic field lines and perform a similar analysis on this issue for 76 events in total by extending the study interval to the end of 2008. Three key parameters, CH proximity, CH area and CH relative position, are involved in the analysis. The new result confirms the previous conclusion that CHs did not show any evident effect on CMEs in causing SEP events. (research papers)

  9. A Real-Time evaluation system for a state-of-charge indication algorithm

    NARCIS (Netherlands)

    Pop, V.; Bergveld, H.J.; Notten, P.H.L.; Regtien, Paulus P.L.

    2005-01-01

    The known methods of State-of-Charge (SoC) indication in portable applications are not accurate enough under all practical conditions. This paper describes a real- time evaluation LabVIEW system for an SoC algorithm, that calculates the SoC in [%] and also the remaining run-time available under the

  10. A real-time evaluation system for a state-of-charge indication algorithm

    NARCIS (Netherlands)

    Pop, V.; Bergveld, H.J.; Notten, P.H.L.; Regtien, P.P.L.

    2005-01-01

    The known methods of State-of-Charge (SoC) indication in portable applications are not accurate enough under all practical conditions. This paper describes a real- time evaluation LabVIEW system for an SoC algorithm, that calculates the SoC in [%] and also the remaining run-time available under the

  11. Assessment of T2-Weighted Coronal Magnetic Resonance Images in the Investigation of Pituitary Lesions

    International Nuclear Information System (INIS)

    Yuksekkaya, Ruken; Aggunlu, Levent; Oner, Yusuf; Celik, Halil; Akpek, Sergin; Celikyay, Fatih

    2014-01-01

    Magnetic resonance imaging is the most important diagnostic method in the investigation of the pituitary lesions. Our aim is to determine whether T2-weighted coronal images may be helpful in the evaluation of the pituitary gland with suspected pituitary adenomas. One hundred and sixty-seven patients were examined prospectively with T2-weighted coronal and T1-weighted coronal images enhanced with intravenous contrast material. The images were evaluated for the presence, the size, the location, and the ancillary signs including sellar floor erosion or ballooning, infindibulary deviation, convexity of the superior border of the gland, diffuse enlargement of the gland, and the invasion of the cavenous sinuses on both images. In forty-six (28%) patients lesions were revealed on both sequences. In twenty-one (12%) patients the lesions that were revealed on the T1-weighted images were not detected on the T2-weighted images. Positive predictive value, negative predictive value, sensitivity, specificity, and diagnostic accuracy rates of T2-weighted coronal images on the detection of the presence of lesions were 100%, 17.4%, 68.7%, 100%, and 87.4%, respectively. Both T2-weighted coronal and T1-weighted coronal images enhanced with intravenous gadolinium-based contrast material are important in the diagnosis of pituitary adenomas. T2-weighted coronal images could be used as a screening tool for the primary evaluation of the pituitary gland

  12. Supervised chaos genetic algorithm based state of charge determination for LiFePO4 batteries in electric vehicles

    Science.gov (United States)

    Shen, Yanqing

    2018-04-01

    LiFePO4 battery is developed rapidly in electric vehicle, whose safety and functional capabilities are influenced greatly by the evaluation of available cell capacity. Added with adaptive switch mechanism, this paper advances a supervised chaos genetic algorithm based state of charge determination method, where a combined state space model is employed to simulate battery dynamics. The method is validated by the experiment data collected from battery test system. Results indicate that the supervised chaos genetic algorithm based state of charge determination method shows great performance with less computation complexity and is little influenced by the unknown initial cell state.

  13. Evidence for the Magnetic Breakout Model in an Equatorial Coronal-hole Jet

    Science.gov (United States)

    Kumar, Pankaj; Karpen, Judith T.; Antiochos, Spiro K.; Wyper, Peter F.; DeVore, C. Richard; DeForest, Craig E.

    2018-02-01

    Small, impulsive jets commonly occur throughout the solar corona, but are especially visible in coronal holes. Evidence is mounting that jets are part of a continuum of eruptions that extends to much larger coronal mass ejections and eruptive flares. Because coronal-hole jets originate in relatively simple magnetic structures, they offer an ideal testbed for theories of energy buildup and release in the full range of solar eruptions. We analyzed an equatorial coronal-hole jet observed by the Solar Dynamics Observatory (SDO)/AIA on 2014 January 9 in which the magnetic-field structure was consistent with the embedded-bipole topology that we identified and modeled previously as an origin of coronal jets. In addition, this event contained a mini-filament, which led to important insights into the energy storage and release mechanisms. SDO/HMI magnetograms revealed footpoint motions in the primary minority-polarity region at the eruption site, but show negligible flux emergence or cancellation for at least 16 hr before the eruption. Therefore, the free energy powering this jet probably came from magnetic shear concentrated at the polarity inversion line within the embedded bipole. We find that the observed activity sequence and its interpretation closely match the predictions of the breakout jet model, strongly supporting the hypothesis that the breakout model can explain solar eruptions on a wide range of scales.

  14. THE CHARGE STATE OF POLYCYCLIC AROMATIC HYDROCARBONS ACROSS REFLECTION NEBULAE: PAH CHARGE BALANCE AND CALIBRATION

    International Nuclear Information System (INIS)

    Boersma, C.; Bregman, J.; Allamandola, L. J.

    2016-01-01

    Low-resolution Spitzer spectral map data (>1700 spectra) of ten reflection nebulae (RNe) fields are analyzed using the data and tools available through the NASA Ames PAH IR Spectroscopic Database. The PAH emission is broken down into PAH charge state using a database fitting approach. Here, the physics of the PAH emission process is taken into account and uses target appropriate parameters, e.g., a stellar radiation model for the exciting star. The breakdown results are combined with results derived using the traditional PAH band strength approach, which interprets particular PAH band strength ratios as proxies for the PAH charge state, e.g., the 6.2/11.2 μ m PAH band strength ratio. These are successfully calibrated against their database equivalent; the PAH ionized fraction ( f i ). The PAH ionized fraction is converted into the PAH ionization parameter, which relates the PAH ionized fraction to the strength of the radiation field, gas temperature and electron density. The behavior of the 12.7 μ m PAH band is evaluated as a tracer for PAH ionization and erosion. The plot of the 8.6 versus 11.2 μ m PAH band strength for the northwest photo-dominated region (PDR) in NGC 7023 is shown to be a robust diagnostic template for the PAH ionized fraction. Remarkably, most of the other RNe fall within the limits set by NGC 7023. Finally, PAH spectroscopic templates are constructed and verified as principal components. Template spectra derived from NGC 7023 and NGC 2023 compare extremely well with each other, with those derived for NGC 7023 successfully reproducing the PAH emission observed from NGC 2023.

  15. THE CHARGE STATE OF POLYCYCLIC AROMATIC HYDROCARBONS ACROSS REFLECTION NEBULAE: PAH CHARGE BALANCE AND CALIBRATION

    Energy Technology Data Exchange (ETDEWEB)

    Boersma, C.; Bregman, J.; Allamandola, L. J., E-mail: Christiaan.Boersma@nasa.gov [NASA Ames Research Center, MS 245-6, Moffett Field, CA 94035-0001 (United States)

    2016-11-20

    Low-resolution Spitzer spectral map data (>1700 spectra) of ten reflection nebulae (RNe) fields are analyzed using the data and tools available through the NASA Ames PAH IR Spectroscopic Database. The PAH emission is broken down into PAH charge state using a database fitting approach. Here, the physics of the PAH emission process is taken into account and uses target appropriate parameters, e.g., a stellar radiation model for the exciting star. The breakdown results are combined with results derived using the traditional PAH band strength approach, which interprets particular PAH band strength ratios as proxies for the PAH charge state, e.g., the 6.2/11.2 μ m PAH band strength ratio. These are successfully calibrated against their database equivalent; the PAH ionized fraction ( f {sub i} ). The PAH ionized fraction is converted into the PAH ionization parameter, which relates the PAH ionized fraction to the strength of the radiation field, gas temperature and electron density. The behavior of the 12.7 μ m PAH band is evaluated as a tracer for PAH ionization and erosion. The plot of the 8.6 versus 11.2 μ m PAH band strength for the northwest photo-dominated region (PDR) in NGC 7023 is shown to be a robust diagnostic template for the PAH ionized fraction. Remarkably, most of the other RNe fall within the limits set by NGC 7023. Finally, PAH spectroscopic templates are constructed and verified as principal components. Template spectra derived from NGC 7023 and NGC 2023 compare extremely well with each other, with those derived for NGC 7023 successfully reproducing the PAH emission observed from NGC 2023.

  16. Characterization of electronic charged states of P-doped Si quantum dots using AFM/Kelvin probe

    International Nuclear Information System (INIS)

    Makihara, Katsunori; Xu, Jun; Ikeda, Mitsuhisa; Murakami, Hideki; Higashi, Seiichiro; Miyazaki, Seiichi

    2006-01-01

    Phosphorous doping to Si quantum dots was performed by a pulse injection of 1% PH 3 diluted with He during the dot formation on thermally grown SiO 2 from thermal decomposition of pure SiH 4 , and electron charging to and discharging from P-doped Si dots were studied to characterize their electronic charged states using a Kelvin probe technique in atomic force microscopy (AFM). The potential change corresponding to the extraction of one electron from each of the P-doped Si dots was observed after applying a tip bias as low as + 0.2 V while for undoped Si dots, with almost the same size as P-doped Si dots, almost the same amount of the potential change was detectable only when the tip bias was increased to ∼ 1 V. It is likely that, for P-doped Si dots, the electron extraction from the conduction band occurs and results in a positively charged state with ionized P donor

  17. Study of the cold charge transfer state separation at the TQ1/PC71 BM interface.

    Science.gov (United States)

    Volpi, Riccardo; Linares, Mathieu

    2017-05-30

    Charge transfer (CT) state separation is one of the most critical processes in the functioning of an organic solar cell. In this article, we study a bilayer of TQ1 and PC 71 BM molecules presenting disorder at the interface, obtained by means of Molecular Dynamics. The study of the CT state splitting can be first analyzed through the CT state splitting diagram, introduced in a previous work. Through this analysis, we identify the possibility of CT state splitting within Marcus Theory in function of the electric field. Once the right range of electric fields has been identified, we perform Kinetic Monte Carlo simulations to estimate percentages and times for the CT state splitting and the free charge carriers collection. Statistical information extracted from these simulations allows us to highlight the importance of polarization and to test the limits of the predictions given by the CT state splitting diagram. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  18. Long-lived, charge-shift states in heterometallic, porphyrin-based dendrimers formed via click chemistry.

    Science.gov (United States)

    Le Pleux, Loïc; Pellegrin, Yann; Blart, Errol; Odobel, Fabrice; Harriman, Anthony

    2011-05-26

    A series of multiporphyrin clusters has been synthesized and characterized in which there exists a logical gradient for either energy or electron transfer between the porphyrins. A central free-base porphyrin (FbP), for example, is equipped with peripheral zinc(II) porphyrins (ZnP) which act as ancillary light harvesters and transfer excitation energy to the FbP under visible light illumination. Additional energy-transfer steps occur at the triplet level, and the series is expanded by including magnesium(II) porphyrins and/or tin(IV) porphyrins as chromophores. Light-induced electron transfer is made possible by incorporating a gold(III) porphyrin (AuP(+)) into the array. Although interesting by themselves, these clusters serve as control compounds by which to understand the photophysical processes occurring within a three-stage dendrimer comprising an AuP(+) core, a second layer formed from four FbP units, and an outer layer containing 12 ZnP residues. Here, illumination into a peripheral ZnP leads to highly efficient electronic energy transfer to FbP, followed by charge transfer to the central AuP(+). Charge recombination within the resultant charge-shift state is intercepted by secondary hole transfer to the ZnP, which occurs with a quantum yield of around 20%. The final charge-shift state survives for some microseconds in fluid solution at room temperature.

  19. Numerically modelling the large scale coronal magnetic field

    Science.gov (United States)

    Panja, Mayukh; Nandi, Dibyendu

    2016-07-01

    The solar corona spews out vast amounts of magnetized plasma into the heliosphere which has a direct impact on the Earth's magnetosphere. Thus it is important that we develop an understanding of the dynamics of the solar corona. With our present technology it has not been possible to generate 3D magnetic maps of the solar corona; this warrants the use of numerical simulations to study the coronal magnetic field. A very popular method of doing this, is to extrapolate the photospheric magnetic field using NLFF or PFSS codes. However the extrapolations at different time intervals are completely independent of each other and do not capture the temporal evolution of magnetic fields. On the other hand full MHD simulations of the global coronal field, apart from being computationally very expensive would be physically less transparent, owing to the large number of free parameters that are typically used in such codes. This brings us to the Magneto-frictional model which is relatively simpler and computationally more economic. We have developed a Magnetofrictional Model, in 3D spherical polar co-ordinates to study the large scale global coronal field. Here we present studies of changing connectivities between active regions, in response to photospheric motions.

  20. Charge collection and pore filling in solid-state dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Snaith, Henry J; Humphry-Baker, Robin; Chen, Peter; Zakeeruddin, Shaik M; Graetzel, Michael; Cesar, Ilkay

    2008-01-01

    The solar to electrical power conversion efficiency for dye-sensitized solar cells (DSCs) incorporating a solid-state organic hole-transporter can be over 5%. However, this is for devices significantly thinner than the optical depth of the active composites and by comparison to the liquid electrolyte based DSCs, which exhibit efficiencies in excess of 10%, more than doubling of this efficiency is clearly attainable if all the steps in the photovoltaic process can be optimized. Two issues are currently being addressed by the field. The first aims at enhancing the electron diffusion length by either reducing the charge recombination or enhancing the charge transport rates. This should enable a larger fraction of photogenerated charges to be collected. The second, though less actively investigated, aims to improve the physical composite formation, which in this instance is the infiltration of mesoporous TiO 2 with the organic hole-transporter 2,2',7,7'-tetrakis(N,N-di-p-methoxypheny-amine)-9,9'-spirobifluorene (spiro-MeOTAD). Here, we perform a broad experimental study to elucidate the limiting factors to the solar cell performance. We first investigate the charge transport and recombination in the solid-state dye-sensitized solar cell under realistic working conditions via small perturbation photovoltage and photocurrent decay measurements. From these measurements we deduce that the electron diffusion length near short-circuit is as long as 20 μm. However, at applied biases approaching open-circuit potential under realistic solar conditions, the diffusion length becomes comparable with the film thickness, ∼2 μm, illustrating that real losses to open-circuit voltage, fill factor and hence efficiency are occurring due to ineffective charge collection. The long diffusion length near short-circuit, on the other hand, illustrates that another process, separate from ineffective charge collection, is rendering the solar cell less than ideal. We investigate the process

  1. Charge collection and pore filling in solid-state dye-sensitized solar cells.

    Science.gov (United States)

    Snaith, Henry J; Humphry-Baker, Robin; Chen, Peter; Cesar, Ilkay; Zakeeruddin, Shaik M; Grätzel, Michael

    2008-10-22

    The solar to electrical power conversion efficiency for dye-sensitized solar cells (DSCs) incorporating a solid-state organic hole-transporter can be over 5%. However, this is for devices significantly thinner than the optical depth of the active composites and by comparison to the liquid electrolyte based DSCs, which exhibit efficiencies in excess of 10%, more than doubling of this efficiency is clearly attainable if all the steps in the photovoltaic process can be optimized. Two issues are currently being addressed by the field. The first aims at enhancing the electron diffusion length by either reducing the charge recombination or enhancing the charge transport rates. This should enable a larger fraction of photogenerated charges to be collected. The second, though less actively investigated, aims to improve the physical composite formation, which in this instance is the infiltration of mesoporous TiO(2) with the organic hole-transporter 2,2',7,7'-tetrakis(N,N-di-p-methoxypheny-amine)-9,9'-spirobifluorene (spiro-MeOTAD). Here, we perform a broad experimental study to elucidate the limiting factors to the solar cell performance. We first investigate the charge transport and recombination in the solid-state dye-sensitized solar cell under realistic working conditions via small perturbation photovoltage and photocurrent decay measurements. From these measurements we deduce that the electron diffusion length near short-circuit is as long as 20 µm. However, at applied biases approaching open-circuit potential under realistic solar conditions, the diffusion length becomes comparable with the film thickness, ∼2 µm, illustrating that real losses to open-circuit voltage, fill factor and hence efficiency are occurring due to ineffective charge collection. The long diffusion length near short-circuit, on the other hand, illustrates that another process, separate from ineffective charge collection, is rendering the solar cell less than ideal. We investigate the

  2. Fracture morphology of AO/OTA 31-A trochanteric fractures: A 3D CT study with an emphasis on coronal fragments.

    Science.gov (United States)

    Cho, Jae-Woo; Kent, William T; Yoon, Yong-Cheol; Kim, Youngwoo; Kim, Hyungon; Jha, Ashutosh; Durai, Senthil Kumar; Oh, Jong-Keon

    2017-02-01

    This study was designed to assess the incidence and morphology of coronal plane fragments in AO/OTA 31-A trochanteric fractures. 156 cases of AO/OTA 31-A trochanteric fractures were retrospectively evaluated. Lateral radiographs were analyzed for the presence of coronal plane fragments followed by analysis of 3D CT reconstructions in these fractures. The incidence of coronal fragments identified on the lateral radiograph and 3D CT reconstructions were both calculated. Coronal fragment morphology was described based upon the origin and exit points of fracture lines and the number of fragments. On plain radiographs, a coronal plane fracture was identified in 59 cases, an incidence of 37.8% (59/156). In comparison, 3D CT reconstructions identified coronal plane fractures in 138 cases for an incidence of 88.4% (138/156). 3D CT reconstructions identified coronal fracture fragments in 81.9% (50/61) of AO/OTA 31-A1 cases, 94.5% (69/73) of 31-A2 cases, and 86.3% (19/22) of 31-A3 cases. Incidence of coronal fractures identified on plain radiographs of 3 AO/OTA 31-A1,A2,A3 groups was lower when compared to the incidence of coronal fractures identified on 3D CT. Of the 138 cases that had coronal plane fracture, 82 cases (59.4%) had a single coronal fragment (GT fragment 35 cases, GLT fragment 19 cases, GLPC fragment 28 cases). The remaining 56 cases (40.5%) had two coronal fragments. There is a high incidence of coronal fragments in intertrochanteric femur fractures when analyzed with 3D CT reconstructions. Our study suggests that these coronal fragments are difficult to identify on plain radiographs. Knowledge of the incidence and morphology of coronal fragments helps to avoid potential intraoperative pitfalls. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Dynamics of the excited state intramolecular charge transfer

    International Nuclear Information System (INIS)

    Joo, T.; Kim, C.H.

    2006-01-01

    The 6-dodecanoyl-2-dimethylaminonaphtalene (laurdan), a derivative of 6-propanoyl- 2-dimethylaminonaphthalene (prodan), has been used as a fluorescent probe in cell imaging, especially in visualizing the lipid rafts by the generalized polarization (GP) images, where GP=(I 440 -I 490 )/(I 440 +I 490 ) with I being the fluorescence intensity. The fluorescence spectrum of laurdan is sensitive to its dipolar environment due to the intramolecular charge transfer (ICT) process in S 1 state, which results in a dual emission from the locally excited (LE) and the ICT states. The ICT process and the solvation of the ICT state are very sensitive to the dipolar nature of the environment. In this work, the ICT of laurdan in ethanol has been studied by femtosecond time resolved fluorescence (TRF), especially TRF spectra measurement without the conventional spectral reconstruction method. TRF probes the excited states exclusively, a unique advantage over the pump/probe transient absorption technique, although time resolution of the TRF is generally lower than transient absorption and the TRF spectra measurement was possible only though the spectral reconstruction. Over the years, critical advances in TRF technique have been made in our group to achieve <50 fs time resolution with direct full spectra measurement capability. Detailed ICT and the subsequent solvation processes can be visualized unambiguously from the TRF spectra. Fig. 1 shows the TRF spectra of laurdan in ethanol at several time delays. Surprisingly, two bands at 433 and 476 nm are clearly visible in the TRF spectra of laurdan even at T = 0 fs. As time increases, the band at 476 nm shifts to the red while its intensity increases. The band at 433 nm also shifts slightly to the red, but loses intensity as time increases. The intensity of the 476 nm band reaches maximum at around 5 ps, where it is roughly twice as intense as that at 0 fs, and stays constant until lifetime decay is noticeable. The spectra were fit by

  4. The Large-scale Coronal Structure of the 2017 August 21 Great American Eclipse: An Assessment of Solar Surface Flux Transport Model Enabled Predictions and Observations

    Science.gov (United States)

    Nandy, Dibyendu; Bhowmik, Prantika; Yeates, Anthony R.; Panda, Suman; Tarafder, Rajashik; Dash, Soumyaranjan

    2018-01-01

    On 2017 August 21, a total solar eclipse swept across the contiguous United States, providing excellent opportunities for diagnostics of the Sun’s corona. The Sun’s coronal structure is notoriously difficult to observe except during solar eclipses; thus, theoretical models must be relied upon for inferring the underlying magnetic structure of the Sun’s outer atmosphere. These models are necessary for understanding the role of magnetic fields in the heating of the corona to a million degrees and the generation of severe space weather. Here we present a methodology for predicting the structure of the coronal field based on model forward runs of a solar surface flux transport model, whose predicted surface field is utilized to extrapolate future coronal magnetic field structures. This prescription was applied to the 2017 August 21 solar eclipse. A post-eclipse analysis shows good agreement between model simulated and observed coronal structures and their locations on the limb. We demonstrate that slow changes in the Sun’s surface magnetic field distribution driven by long-term flux emergence and its evolution governs large-scale coronal structures with a (plausibly cycle-phase dependent) dynamical memory timescale on the order of a few solar rotations, opening up the possibility for large-scale, global corona predictions at least a month in advance.

  5. 77 FR 24537 - Draft Standards and Best Practices for Interaction Between Medical Examiner/Coroner and Organ and...

    Science.gov (United States)

    2012-04-24

    ... Best Practices for Interaction Between Medical Examiner/Coroner and Organ and Tissue Procurement... Committee Standards and Best Practices for Interaction Between Medical Examiner/Coroner Offices and Organ... coroner/medical examiner office representatives, law enforcement agencies, organizations, and all other...

  6. Unraveling the Solution-State Supramolecular Structures of Donor-Acceptor Polymers and their Influence on Solid-State Morphology and Charge-Transport Properties.

    Science.gov (United States)

    Zheng, Yu-Qing; Yao, Ze-Fan; Lei, Ting; Dou, Jin-Hu; Yang, Chi-Yuan; Zou, Lin; Meng, Xiangyi; Ma, Wei; Wang, Jie-Yu; Pei, Jian

    2017-11-01

    Polymer self-assembly in solution prior to film fabrication makes solution-state structures critical for their solid-state packing and optoelectronic properties. However, unraveling the solution-state supramolecular structures is challenging, not to mention establishing a clear relationship between the solution-state structure and the charge-transport properties in field-effect transistors. Here, for the first time, it is revealed that the thin-film morphology of a conjugated polymer inherits the features of its solution-state supramolecular structures. A "solution-state supramolecular structure control" strategy is proposed to increase the electron mobility of a benzodifurandione-based oligo(p-phenylene vinylene) (BDOPV)-based polymer. It is shown that the solution-state structures of the BDOPV-based conjugated polymer can be tuned such that it forms a 1D rod-like structure in good solvent and a 2D lamellar structure in poor solvent. By tuning the solution-state structure, films with high crystallinity and good interdomain connectivity are obtained. The electron mobility significantly increases from the original value of 1.8 to 3.2 cm 2 V -1 s -1 . This work demonstrates that "solution-state supramolecular structure" control is critical for understanding and optimization of the thin-film morphology and charge-transport properties of conjugated polymers. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Quasi-bound state resonances of charged massive scalar fields in the near-extremal Reissner-Nordstroem black-hole spacetime

    Energy Technology Data Exchange (ETDEWEB)

    Hod, Shahar [The Ruppin Academic Center, Emeq Hefer (Israel); The Hadassah Academic College, Jerusalem (Israel)

    2017-05-15

    The quasi-bound states of charged massive scalar fields in the near-extremal charged Reissner-Nordstroem black-hole spacetime are studied analytically. These discrete resonant modes of the composed black-hole-field system are characterized by the physically motivated boundary condition of ingoing waves at the black-hole horizon and exponentially decaying (bounded) radial eigenfunctions at spatial infinity. Solving the Klein-Gordon wave equation for the linearized scalar fields in the black-hole spacetime, we derive a remarkably compact analytical formula for the complex frequency spectrum which characterizes the quasi-bound state resonances of the composed Reissner-Nordstroem-black-hole-charged-massive-scalar-field system. (orig.)

  8. Correlation of Mn charge state with the electrical resistivity of Mn doped indium tin oxide thin films

    KAUST Repository

    Kumar, S. R. Sarath

    2010-09-15

    Correlation of charge state of Mn with the increase in resistivity with Mn concentration is demonstrated in Mn-doped indium tin oxide films. Bonding analysis shows that Mn 2p3/2 core level can be deconvoluted into three components corresponding to Mn2+ and Mn4+ with binding energies 640.8 eV and 642.7 eV, respectively, and a Mn2+ satellite at ∼5.4 eV away from the Mn2+ peak. The presence of the satellite peak unambiguously proves that Mn exists in the +2 charge state. The ratio of concentration of Mn2+ to Mn4+ of ∼4:1 suggests that charge compensation occurs in the n-type films causing the resistivity increase.

  9. Correlation of Mn charge state with the electrical resistivity of Mn doped indium tin oxide thin films

    KAUST Repository

    Kumar, S. R. Sarath; Hedhili, Mohamed N.; Alshareef, Husam N.; Kasiviswanathan, S.

    2010-01-01

    Correlation of charge state of Mn with the increase in resistivity with Mn concentration is demonstrated in Mn-doped indium tin oxide films. Bonding analysis shows that Mn 2p3/2 core level can be deconvoluted into three components corresponding to Mn2+ and Mn4+ with binding energies 640.8 eV and 642.7 eV, respectively, and a Mn2+ satellite at ∼5.4 eV away from the Mn2+ peak. The presence of the satellite peak unambiguously proves that Mn exists in the +2 charge state. The ratio of concentration of Mn2+ to Mn4+ of ∼4:1 suggests that charge compensation occurs in the n-type films causing the resistivity increase.

  10. Moving Towards a State of the Art Charge-Exchange Reaction Code

    Science.gov (United States)

    Poxon-Pearson, Terri; Nunes, Filomena; Potel, Gregory

    2017-09-01

    Charge-exchange reactions have a wide range of applications, including late stellar evolution, constraining the matrix elements for neutrinoless double β-decay, and exploring symmetry energy and other aspects of exotic nuclear matter. Still, much of the reaction theory needed to describe these transitions is underdeveloped and relies on assumptions and simplifications that are often extended outside of their region of validity. In this work, we have begun to move towards a state of the art charge-exchange reaction code. As a first step, we focus on Fermi transitions using a Lane potential in a few body, Distorted Wave Born Approximation (DWBA) framework. We have focused on maintaining a modular structure for the code so we can later incorporate complications such as nonlocality, breakup, and microscopic inputs. Results using this new charge-exchange code will be shown compared to the analysis in for the case of 48Ca(p,n)48Sc. This work was supported in part by the National Nuclear Security Administration under the Stewardship Science Academic Alliances program through the U.S. DOE Cooperative Agreement No. DE- FG52-08NA2855.

  11. Charge Carrier Generation Followed by Triplet State Formation, Annihilation, and Carrier Recreation in PBDTTT-C:PC 60 BM Photovoltaic Blends

    KAUST Repository

    Gehrig, Dominik W.

    2015-05-22

    Triplet state formation after photoexcitation of low-bandgap polymer:fullerene blends has recently been demonstrated, however, the precise mechanism and its impact on solar cell performance is still under debate. Here, we study exciton dissociation, charge carrier generation and triplet state formation in low-bandgap polymer PBDTTT-C:PC60BM bulk heterojunction photovoltaic blends by a combination of fs-µs broadband Vis-NIR transient absorption (TA) pump-probe spectroscopy and multivariate curve resolution (MCR) data analysis. We found sub-ps exciton dissociation and charge generation followed by sub-ns triplet state creation. The carrier dynamics and triplet state dynamics exhibited a very pronounced intensity dependence indicating non-geminate recombination of free carriers is the origin of triplet formation in these blends. Triplets were found to be the dominant state present on the nanosecond timescale. Surprisingly, the carrier population increased again on the ns-µs timescale. We attribute this to triplet-triplet annihilation and the formation of higher energy excited states that subsequently underwent charge transfer. This unique dip and recovery of the charge population is a clear indication that triplets are formed by non-geminate recombination, as such a kinetic is incompatible with a monomolecular triplet state formation process.

  12. Charge Carrier Generation Followed by Triplet State Formation, Annihilation, and Carrier Recreation in PBDTTT-C:PC 60 BM Photovoltaic Blends

    KAUST Repository

    Gehrig, Dominik W.; Howard, Ian A.; Laquai, Fré dé ric

    2015-01-01

    Triplet state formation after photoexcitation of low-bandgap polymer:fullerene blends has recently been demonstrated, however, the precise mechanism and its impact on solar cell performance is still under debate. Here, we study exciton dissociation, charge carrier generation and triplet state formation in low-bandgap polymer PBDTTT-C:PC60BM bulk heterojunction photovoltaic blends by a combination of fs-µs broadband Vis-NIR transient absorption (TA) pump-probe spectroscopy and multivariate curve resolution (MCR) data analysis. We found sub-ps exciton dissociation and charge generation followed by sub-ns triplet state creation. The carrier dynamics and triplet state dynamics exhibited a very pronounced intensity dependence indicating non-geminate recombination of free carriers is the origin of triplet formation in these blends. Triplets were found to be the dominant state present on the nanosecond timescale. Surprisingly, the carrier population increased again on the ns-µs timescale. We attribute this to triplet-triplet annihilation and the formation of higher energy excited states that subsequently underwent charge transfer. This unique dip and recovery of the charge population is a clear indication that triplets are formed by non-geminate recombination, as such a kinetic is incompatible with a monomolecular triplet state formation process.

  13. BREIT code: Analytical solution of the balance rate equations for charge-state evolutions of heavy-ion beams in matter

    Energy Technology Data Exchange (ETDEWEB)

    Winckler, N., E-mail: n.winckler@gsi.de [GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Rybalchenko, A. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Shevelko, V.P. [P.N. Lebedev Physical Institute, 119991 Moscow (Russian Federation); Al-Turany, M. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt (Germany); CERN, European Organization for Nuclear Research, 1211 Geneve 23 (Switzerland); Kollegger, T. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Stöhlker, Th. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Helmholtz-Institute Jena, D-07743 Jena (Germany); Institut für Optik und Quantenelektronik, Friedrich-Schiller-Universität, D-07743 Jena (Germany)

    2017-02-01

    A detailed description of a recently developed BREIT computer code (Balance Rate Equations of Ion Transportation) for calculating charge-state fractions of ion beams passing through matter is presented. The code is based on the analytical solutions of the differential balance equations for the charge-state fractions as a function of the target thickness and can be used for calculating the ion evolutions in gaseous, solid and plasma targets. The BREIT code is available on-line and requires the charge-changing cross sections and initial conditions in the input file. The eigenvalue decomposition method, applied to obtain the analytical solutions of the rate equations, is described in the paper. Calculations of non-equilibrium and equilibrium charge-state fractions, performed by the BREIT code, are compared with experimental data and results of other codes for ion beams in gaseous and solid targets. Ability and limitations of the BREIT code are discussed in detail.

  14. LEDs for the Implementation of Advanced Hydrogenation Using Hydrogen Charge-State Control

    Directory of Open Access Journals (Sweden)

    Chee Mun Chong

    2018-01-01

    Full Text Available Light-induced degradation (LID of p-type Cz solar cells has plagued the industry for many decades. However, in recent years, new techniques for solving this LID have been developed, with hydrogen passivation of the boron-oxygen defects appearing to be an important contributor to the solution. Advanced hydrogenation approaches involving the control of the charge state for the hydrogen atoms in silicon to enhance their diffusivity and reactivity are developed and evaluated in this work for commercial application using a prototype industrial tool in conjunction with solar cells manufactured on commercial production lines. This prototype tool, unlike the previous successful laser-based laboratory approaches, is based on the use of LEDs for controlling the charge state of the hydrogen atoms. The illumination from the LEDs is also used in this work to passivate process-induced defects and contamination from the respective production lines with significant improvements in both efficiency and stability. The results indicate that the low-cost LED-based industrial tool performs as well as the laser-based laboratory tool for implementing these advanced hydrogen passivation approaches.

  15. 12 CFR 7.4001 - Charging interest at rates permitted competing institutions; charging interest to corporate...

    Science.gov (United States)

    2010-01-01

    ... institutions; charging interest to corporate borrowers. 7.4001 Section 7.4001 Banks and Banking COMPTROLLER OF... interest at rates permitted competing institutions; charging interest to corporate borrowers. (a... the law of that state. If state law permits different interest charges on specified classes of loans...

  16. Coulombic charge ice

    Science.gov (United States)

    McClarty, P. A.; O'Brien, A.; Pollmann, F.

    2014-05-01

    We consider a classical model of charges ±q on a pyrochlore lattice in the presence of long-range Coulomb interactions. This model first appeared in the early literature on charge order in magnetite [P. W. Anderson, Phys. Rev. 102, 1008 (1956), 10.1103/PhysRev.102.1008]. In the limit where the interactions become short ranged, the model has a ground state with an extensive entropy and dipolar charge-charge correlations. When long-range interactions are introduced, the exact degeneracy is broken. We study the thermodynamics of the model and show the presence of a correlated charge liquid within a temperature window in which the physics is well described as a liquid of screened charged defects. The structure factor in this phase, which has smeared pinch points at the reciprocal lattice points, may be used to detect charge ice experimentally. In addition, the model exhibits fractionally charged excitations ±q/2 which are shown to interact via a 1/r potential. At lower temperatures, the model exhibits a transition to a long-range ordered phase. We are able to treat the Coulombic charge ice model and the dipolar spin ice model on an equal footing by mapping both to a constrained charge model on the diamond lattice. We find that states of the two ice models are related by a staggering field which is reflected in the energetics of these two models. From this perspective, we can understand the origin of the spin ice and charge ice ground states as coming from a dipolar model on a diamond lattice. We study the properties of charge ice in an external electric field, finding that the correlated liquid is robust to the presence of a field in contrast to the case of spin ice in a magnetic field. Finally, we comment on the transport properties of Coulombic charge ice in the correlated liquid phase.

  17. In situ X-ray near-edge absorption spectroscopy investigation of the state of charge of all-vanadium redox flow batteries.

    Science.gov (United States)

    Jia, Chuankun; Liu, Qi; Sun, Cheng-Jun; Yang, Fan; Ren, Yang; Heald, Steve M; Liu, Yadong; Li, Zhe-Fei; Lu, Wenquan; Xie, Jian

    2014-10-22

    Synchrotron-based in situ X-ray near-edge absorption spectroscopy (XANES) has been used to study the valence state evolution of the vanadium ion for both the catholyte and anolyte in all-vanadium redox flow batteries (VRB) under realistic cycling conditions. The results indicate that, when using the widely used charge-discharge profile during the first charge process (charging the VRB cell to 1.65 V under a constant current mode), the vanadium ion valence did not reach V(V) in the catholyte and did not reach V(II) in the anolyte. Consequently, the state of charge (SOC) for the VRB cell was only 82%, far below the desired 100% SOC. Thus, such incompletely charged mix electrolytes results in not only wasting the electrolytes but also decreasing the cell performance in the following cycles. On the basis of our study, we proposed a new charge-discharge profile (first charged at a constant current mode up to 1.65 V and then continuously charged at a constant voltage mode until the capacity was close to the theoretical value) for the first charge process that achieved 100% SOC after the initial charge process. Utilizing this new charge-discharge profile, the theoretical charge capacity and the full utilization of electrolytes has been achieved, thus having a significant impact on the cost reduction of the electrolytes in VRB.

  18. CORONAL DENSITY STRUCTURE AND ITS ROLE IN WAVE DAMPING IN LOOPS

    Energy Technology Data Exchange (ETDEWEB)

    Cargill, P. J. [Space and Atmospheric Physics, The Blackett Laboratory, Imperial College, London SW7 2BW (United Kingdom); De Moortel, I.; Kiddie, G., E-mail: p.cargill@imperial.ac.uk [School of Mathematics and Statistics, University of St Andrews, St Andrews, Scotland KY16 9SS (United Kingdom)

    2016-05-20

    It has long been established that gradients in the Alfvén speed, and in particular the plasma density, are an essential part of the damping of waves in the magnetically closed solar corona by mechanisms such as resonant absorption and phase mixing. While models of wave damping often assume a fixed density gradient, in this paper the self-consistency of such calculations is assessed by examining the temporal evolution of the coronal density. It is shown conceptually that for some coronal structures, density gradients can evolve in a way that the wave-damping processes are inhibited. For the case of phase mixing we argue that (a) wave heating cannot sustain the assumed density structure and (b) inclusion of feedback of the heating on the density gradient can lead to a highly structured density, although on long timescales. In addition, transport coefficients well in excess of classical are required to maintain the observed coronal density. Hence, the heating of closed coronal structures by global oscillations may face problems arising from the assumption of a fixed density gradient, and the rapid damping of oscillations may have to be accompanied by a separate (non-wave-based) heating mechanism to sustain the required density structuring.

  19. ON THE CONNECTION BETWEEN PROPAGATING SOLAR CORONAL DISTURBANCES AND CHROMOSPHERIC FOOTPOINTS

    Energy Technology Data Exchange (ETDEWEB)

    Bryans, P.; McIntosh, S. W.; Moortel, I. De [High Altitude Observatory, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307 (United States); Pontieu, B. De [Lockheed Martin Solar and Astrophysics Lab, Org. A021S, Bldg. 252, 3251 Hanover Street, Palo Alto, CA 94304 (United States)

    2016-09-20

    The Interface Region Imaging Spectrograph ( IRIS ) provides an unparalleled opportunity to explore the (thermal) interface between the chromosphere, transition region, and the coronal plasma observed by the Atmospheric Imaging Assembly (AIA) of the Solar Dynamics Observatory ( SDO ). The SDO /AIA observations of coronal loop footpoints show strong recurring upward propagating signals—“propagating coronal disturbances” (PCDs) with apparent speeds of the order of 100–120 km s{sup −1}. That signal has a clear signature in the slit-jaw images of IRIS in addition to identifiable spectral signatures and diagnostics in the Mg iih (2803 Å) line. In analyzing the Mg iih line, we are able to observe the presence of magnetoacoustic shock waves that are also present in the vicinity of the coronal loop footpoints. We see there is enough of a correspondence between the shock propagation in Mg iih, the evolution of the Si iv line profiles, and the PCD evolution to indicate that these waves are an important ingredient for PCDs. In addition, the strong flows in the jet-like features in the IRIS Si iv slit-jaw images are also associated with PCDs, such that waves and flows both appear to be contributing to the signals observed at the footpoints of PCDs.

  20. MRI of the popliteofibular ligament: isotropic 3D WE-DESS versus coronal oblique fat-suppressed T2W MRI

    International Nuclear Information System (INIS)

    Rajeswaran, G.; Lee, J.C.; Healy, J.C.

    2007-01-01

    The objective was to compare isotropic 3D water excitation double-echo steady state (WE-DESS) MRI with coronal oblique fat-suppressed T2-weighted (FS T2W) images in the identification of the popliteofibular ligament (PFL). A prospective analysis of 122 consecutive knee MRIs was performed in patients referred for knee pain from the orthopaedic clinic. In addition to the standard knee sequences, isotropic WE-DESS volume acquisition through the whole knee and coronal oblique FS T2W fast spin echo sequences through the posterolateral corner were obtained. The presence of the popliteus and biceps femoris tendons, lateral collateral and PFL was documented. Anterior cruciate ligament injury was present in 33 cases and these were excluded from the study because of the risk of associated PFL injury, leaving a total of 89 cases. Of the 42 patients in whom arthroscopic evaluation was subsequently obtained, none were found to have an injury to the PFL. The lateral collateral ligament, biceps femoris and popliteus tendon were identified in all cases on all sequences. The PFL was seen in 81 (91.0%; 95% CI 85.1-97.0%) patients using the WE-DESS sequence and 63 (70.8%; 95% CI 61.3-80.2%) patients using the coronal oblique FS T2W sequence, a statistically significant difference (p < 0.00005). Isotropic 3D WE-DESS MRI significantly enhances our ability to identify the popliteofibular ligament compared with coronal oblique fat-suppressed T2-weighted images. (orig.)

  1. MHD modeling of coronal loops: the transition region throat

    Science.gov (United States)

    Guarrasi, M.; Reale, F.; Orlando, S.; Mignone, A.; Klimchuk, J. A.

    2014-04-01

    Context. The expansion of coronal loops in the transition region may considerably influence the diagnostics of the plasma emission measure. The cross-sectional area of the loops is expected to depend on the temperature and pressure, and might be sensitive to the heating rate. Aims: The approach here is to study the area response to slow changes in the coronal heating rate, and check the current interpretation in terms of steady heating models. Methods: We study the area response with a time-dependent 2D magnetohydrodynamic (MHD) loop model, including the description of the expanding magnetic field, coronal heating and losses by thermal conduction, and radiation from optically thin plasma. We run a simulation for a loop 50 Mm long and quasi-statically heated to about 4 MK. Results: We find that the area can change substantially with the quasi-steady heating rate, e.g., by ~40% at 0.5 MK as the loop temperature varies between 1 MK and 4 MK, and, therefore, affects the interpretation of the differential emission measure vs. temperature (DEM(T)) curves. The movie associated to Fig. 4 is available in electronic form at http://www.aanda.org

  2. A Bayesian Approach to Period Searching in Solar Coronal Loops

    Energy Technology Data Exchange (ETDEWEB)

    Scherrer, Bryan; McKenzie, David [Montana State University, P.O. Box 173840 Bozeman, MT 59717-3840 (United States)

    2017-03-01

    We have applied a Bayesian generalized Lomb–Scargle period searching algorithm to movies of coronal loop images obtained with the Hinode X-ray Telescope (XRT) to search for evidence of periodicities that would indicate resonant heating of the loops. The algorithm makes as its only assumption that there is a single sinusoidal signal within each light curve of the data. Both the amplitudes and noise are taken as free parameters. It is argued that this procedure should be used alongside Fourier and wavelet analyses to more accurately extract periodic intensity modulations in coronal loops. The data analyzed are from XRT Observation Program 129C: “MHD Wave Heating (Thin Filters),” which occurred during 2006 November 13 and focused on active region 10293, which included coronal loops. The first data set spans approximately 10 min with an average cadence of 2 s, 2″ per pixel resolution, and used the Al-mesh analysis filter. The second data set spans approximately 4 min with a 3 s average cadence, 1″ per pixel resolution, and used the Al-poly analysis filter. The final data set spans approximately 22 min at a 6 s average cadence, and used the Al-poly analysis filter. In total, 55 periods of sinusoidal coronal loop oscillations between 5.5 and 59.6 s are discussed, supporting proposals in the literature that resonant absorption of magnetic waves is a viable mechanism for depositing energy in the corona.

  3. OBSERVATIONAL SIGNATURES OF THE CORONAL KINK INSTABILITY WITH THERMAL CONDUCTION

    International Nuclear Information System (INIS)

    Botha, G. J. J.; Arber, T. D.; Srivastava, Abhishek K.

    2012-01-01

    It is known from numerical simulations that thermal conduction along magnetic field lines plays an important role in the evolution of the kink instability in coronal loops. This study presents the observational signatures of the kink instability in long coronal loops when parallel thermal conduction is included. The three-dimensional nonlinear magnetohydrodynamic equations are solved numerically to simulate the evolution of a coronal loop that is initially in an unstable equilibrium. The loop has length 80 Mm, width 8 Mm, and an initial maximum twist of Φ = 11.5π, where Φ is a function of the radius. The initial loop parameters are obtained from a highly twisted loop observed in the Transition Region and Coronal Explorer (TRACE) 171 Å wave band. Synthetic observables are generated from the data. These observables include spatial and temporal averaging to account for the resolution and exposure times of TRACE images. Parallel thermal conduction reduces the maximum local temperature by up to an order of magnitude. This means that different spectral lines are formed and different internal loop structures are visible with or without the inclusion of thermal conduction. However, the response functions sample a broad range of temperatures. The result is that the inclusion of parallel thermal conductivity does not have as large an impact on observational signatures as the order of magnitude reduction in the maximum temperature would suggest; the net effect is a blurring of internal features of the loop structure.

  4. Fault lines in forensic medical toxicology in Ireland exposed through replies of pathologists and coroners to anonymous questionnaires.

    Science.gov (United States)

    Tormey, William P; Borovickova, Ingrid; Moore, Tara M

    2014-01-01

    The attitudes and experiences of pathologists and coroners to the provision of biochemical forensic toxicology in the Republic of Ireland were determined using separate questionnaires to each group anonymously. Replies were received from 36/88 (41%) of pathologists and 19/71 (27%) of coroners. 37% of coroners considered that histopathologists give an adequate opinion in forensic toxicology yet 58% of pathologists reported that they did not have adequate access to expert medical interpretative toxicological opinion. For drug-drug interactions and metabolic diseases, 69% of pathologists were unhappy with the processes and 68% of coroner replies did not know if vitreous samples were used appropriately. There is a clear requirement for retraining of coroners and for the appointment of medical toxicology expertise to improve the quality of service for coroners.

  5. Shear-induced inflation of coronal magnetic fields

    International Nuclear Information System (INIS)

    Klimchuk, J.A.

    1990-01-01

    Using numerical models of force-free magnetic fields, the shearing of footprints in arcade geometries leading to an inflation of the coronal magnetic field was examined. For each of the shear profiles considered, all of the field lines become elevated compared with the potential field. This includes cases where the shear is concentrated well away from the arcade axis, such that B(sub z), the component of field parallel to the axis, increases outward to produce an inward B(sub z) squared/8 pi magnetic pressure gradient force. These results contrast with an earlier claim, shown to be incorrect, that field lines can sometimes become depressed as a result of shear. It is conjectured that an inflation of the entire field will always result from the shearing of simple arcade configurations. These results have implications for prominence formation, the interplanetary magnetic flux, and possibly also coronal holes. 38 refs

  6. Thermal instabilities in magnetically confined plasmas: Solar coronal loops

    International Nuclear Information System (INIS)

    Habbal, S.R.; Rosner, R.

    1979-01-01

    The thermal stability of confined solar coronal structures (''loops'') is investigated, following both normal mode and a new, global instability analysis. We demonstrate that: (a) normal mode analysis shows modes with size scales comparable to that of loops to be unstable, but to be strongly affected by the loop boundary conditions; (b) a global analysis, based upon variation of the total loop energy losses and gains, yields loop stability conditions for global modes dependent upon the coronal loop heating process, with magnetically coupled heating processes giving marginal stability. The connection between the present analysis and the minimum flux corona of Hearn is also discussed

  7. The state of itinerant charge carriers and thermoelectric effects in correlated oxide metals

    International Nuclear Information System (INIS)

    Kuzemsky, A.L.; Abdus Salam International Centre for Theoretical Physics, Trieste

    2000-10-01

    We analyzed the physics of transport processes and, in particular, the thermoelectric power in the mercurocuprates and other cuprates to get a better insight into the state of the carriers in these compounds. The actual problems related to the complicated mechanisms of carriers scattering above Tc are discussed. The experimental studies of thermoelectric power showed that the state of carriers in cuprates can be influenced by many complicated scattering processes, however the underlying mechanism for the linear decreasing of the TEP with increasing the temperature for most hole-doped HTSC cuprates is still not yet known. The actual problems related to the complicated mechanisms of carriers scattering above Tc are discussed for a few models of charge transport. A comparison between the analytical and experimental results is also made. It is concluded that the crucial factor for the understanding of the transport properties of correlated oxide metals is the nature of itinerant charge carriers, i.e. renormalized quasiparticles. (author)

  8. Characteristics of Low-latitude Coronal Holes near the Maximum of Solar Cycle 24

    DEFF Research Database (Denmark)

    Hofmeister, Stefan J.; Veronig, Astrid; Reiss, Martin A.

    2017-01-01

    We investigate the statistics of 288 low-latitude coronal holes extracted from SDO/AIA-193 filtergrams over the time range of 2011 January 01–2013 December 31. We analyze the distribution of characteristic coronal hole properties, such as the areas, mean AIA-193 intensities, and mean magnetic fie...

  9. Assessment of Coronal Radiographic Parameters of the Spine in the Treatment of Adolescent Idiopathic Scoliosis

    Directory of Open Access Journals (Sweden)

    Mohsen Karami

    2016-10-01

    Preoperative coronal balance is very important to make a balanced spine after surgery. Other parameters like Lenke classification or main thoracic overcorrection did not affect postoperative coronal decompensation.

  10. State-selective charge transfer and excitation in ion-ion interactions at intermediate and high energies

    International Nuclear Information System (INIS)

    Samanta, R; Purkait, M

    2012-01-01

    Boundary Corrected Continuum Intermediate State (BCCIS) approximation and Classical Trajectory Monte Carlo (CTMC) methods are applied to calculate the charge transfer and excitation cross sections for ion-ion collisions.

  11. Coronal and local thermodynamic equilibriums in a hollow cathode discharge

    International Nuclear Information System (INIS)

    Zheng Xutao

    2005-01-01

    A characteristic two-section profile of excited-state populations is observed in a hollow cathode discharge and is explained by coexistence of the coronal equilibrium (CE) and the local thermodynamic equilibrium (LTE). At helium pressure 0.1 Torr and cathode current 200-300 mA, vacuum ultraviolet radiations from He I 1snp 1 P (n=2-16) and He II np 2 P (n=2-14) are resolved with a 2.2-M McPherson spectrometer. Relative populations of these states are deduced from the discrete line intensities and are plotted against energy levels. For both the He I and He II series, as energy level increases, populations of high-n (n>10) states are found to decrease much more quickly than low-n (n<7) populations. While low-n populations are described with the CE dominated by direct electron-impact excitations, high-n populations are fitted with the LTE to calculate the population temperatures of gas atoms and ions. Validities of the CE and LTE in different n-ranges are considered on the competition between radiative decays of the excited states and their collisions with gas atoms. (author)

  12. Research on State-of-Charge (SOC) estimation using current integration based on temperature compensation

    Science.gov (United States)

    Yin, J.; Shen, Y.; Liu, X. T.; Zeng, G. J.; Liu, D. C.

    2017-11-01

    The traditional current integral method for the state-of-charge (SOC) estimation has an unusable estimation accuracy because of the current measuring error. This paper proposed a closed-loop temperature compensation method to improve the SOC estimation accuracy of current integral method by eliminating temperature drift. Through circuit simulation result in Multisim, the stability of current measuring accuracy is improved by more than 10 times. In a designed 70 charge-discharge experimental circle, the SOC estimation error with temperature compensation had 30 times less than error in normal situation without compensation.

  13. The importance of a hot-sequential mechanism in triplet-state formation by charge recombination in reaction centers of bacterial photosynthesis

    International Nuclear Information System (INIS)

    Saito, K.; Mukai, K.; Sumi, H.

    2006-01-01

    In photosynthesis, pigment-excitation energies in the antenna system produced by light harvesting are transferred among antenna pigments toward the core antenna, where they are captured by the reaction center and initially fixed in the form of a charge separation. Primary charge separation between an oxidized special pair (P + ) and a reduced bacteriopheohytin (H - ) is occasionally intervened by recombination, and a spin-triplet state ( 3 P*) is formed on P in the bacterial reaction center. The 3 P* state is harmful to bio-organisms, inducing the formation of the highly damaging singlet oxygen species. Therefore, understanding the 3 P*-formation mechanism is important. The 3 P* formation is mediated by a state |m> of intermediate charge separation between P and the accessory chlorophyll, which is located between P and H. It will be shown theoretically in the present work that at room temperature, not only the mechanism of superexchange by quantum-mechanical virtual mediation at |m>, but also a hot-sequential mechanism contributes to the mediation. In the latter, although |m> is produced as a real state, the final state 3 P* is quickly formed during thermalization of phonons in the protein matrix in |m>. In the former, the final state is formed more quickly before dephasing-thermalization of phonons in |m>. 3 P* is unistep formed from the charge-separated state in the both mechanisms

  14. A Consistent Derivation of the Impedance of a Lithium-Ion Battery Electrode and its Dependency on the State-of-Charge

    International Nuclear Information System (INIS)

    Schönleber, M.; Uhlmann, C.; Braun, P.; Weber, A.; Ivers-Tiffée, E.

    2017-01-01

    Highlights: •A derivation of the impedance model of a Lithium-Ion battery electrode is given. •The dependency of all partial impedances on the State-of-Charge is revealed. •The lasting disagreement in how to model solid-state diffusion is settled. •A solid starting point to derive models of any complexity is provided. •The connection between differential capacity and solid-state diffusion is revealed. -- Abstract: A derivation of the fundamental impedance of a Lithium-Ion battery electrode is given, exemplarily conducted for a solid thin-film electrode. The focus of this derivation is not on developing a model which is able to reproduce the exact behaviour of a given electrode, but rather on deriving its fundamental characteristics from few and intuitive assumptions in a simple and transparent way. It is thus shown, that the fundamental impedance of a solid thin-film electrode consists of an RC-element for charge-transfer, a Finite-Length Warburg element for diffusion in the electrolyte and a Finite-Space Warburg element for diffusion in the solid-state. The use of a Finite-Length Warburg element with a serially connected capacitor for modelling diffusion in the solid-state is thus indicated to be physically questionable. In addition, the theoretically expected behaviour of charge-transfer and solid-state diffusion on the degree of lithiation (State-of-Charge) is derived and discussed.

  15. Evidence for excited state intramolecular charge transfer in benzazole-based pseudo-stilbenes.

    Science.gov (United States)

    Santos, Fabiano da Silveira; Descalzo, Rodrigo Roceti; Gonçalves, Paulo Fernando Bruno; Benvenutti, Edilson Valmir; Rodembusch, Fabiano Severo

    2012-08-21

    Two azo compounds were obtained through the diazotization reaction of aminobenzazole derivatives and N,N-dimethylaniline using clay montmorillonite KSF as catalyst. The synthesized dyes were characterized using elemental analysis, Fourier transform infrared spectroscopy, and (13)C and (1)H NMR spectroscopy in solution. Their photophysical behavior was studied using UV-vis and steady-state fluorescence in solution. These dyes present intense absorption in the blue region. The spectral features of the azo compounds can be related to the pseudo-stilbene type as well as the E isomer of the dyes. Excitation at the absorption maxima does not produce emissive species in the excited state. However, excitation around 350 nm allowed dual emission of fluorescence, from both a locally excited (LE, short wavelength) and an intramolecular charge transfer (ICT, long wavelength) state, which was corroborated by a linear relation of the fluorescence maximum (ν(max)) versus the solvent polarity function (Δf) from the Lippert-Mataga correlation. Evidence of TICT in these dyes was discussed from the viscosity dependence of the fluorescence intensity in the ICT emission band. Theoretical calculations were also performed in order to study the geometry and charge distribution of the dyes in their ground and excited electronic states. Using DFT methods at the theoretical levels BLYP/Aug-cc-pVDZ, for geometry optimizations and frequency calculations, and B3LYP/6-311+G(2d), for single-point energy evaluations, the calculations revealed that the least energetic and most intense photon absorption leads to a very polar excited state that relaxes non-radioactively, which can be associated with photochemical isomerization.

  16. MINI-FILAMENT ERUPTION AS THE INITIATION OF A JET ALONG CORONAL LOOPS

    International Nuclear Information System (INIS)

    Hong, Junchao; Jiang, Yunchun; Yang, Jiayan; Yang, Bo; Xu, Zhe; Xiang, Yongyuan

    2016-01-01

    Minifilament eruptions (MFEs) and coronal jets are different types of solar small-scale explosive events. We report an MFE observed at the New Vacuum Solar Telescope (NVST). As seen in the NVST H α images, during the rising phase, the minifilament erupts outward orthogonally to its length, accompanied with a flare-like brightening at the bottom. Afterward, dark materials are found to possibly extend along the axis of the expanded filament body. The MFE is analogous to large filament eruptions. However, a simultaneous observation of the Solar Dynamics Observatory shows that a jet is initiated and flows out along nearby coronal loops during the rising phase of the MFE. Meanwhile, small hot loops, which connect the original eruptive site of the minifilament to the footpoints of the coronal loops, are formed successively. A differential emission measure analysis demonstrates that, on the top of the new small loops, a hot cusp structure exists. We conjecture that the magnetic fields of the MFE interact with magnetic fields of the coronal loops. This interaction is interpreted as magnetic reconnection that produces the jet and the small hot loops.

  17. MINI-FILAMENT ERUPTION AS THE INITIATION OF A JET ALONG CORONAL LOOPS

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Junchao; Jiang, Yunchun; Yang, Jiayan; Yang, Bo; Xu, Zhe; Xiang, Yongyuan, E-mail: hjcsolar@ynao.ac.cn [Yunnan Observatories, Chinese Academy of Sciences, Kunming 650011 (China)

    2016-10-20

    Minifilament eruptions (MFEs) and coronal jets are different types of solar small-scale explosive events. We report an MFE observed at the New Vacuum Solar Telescope (NVST). As seen in the NVST H α images, during the rising phase, the minifilament erupts outward orthogonally to its length, accompanied with a flare-like brightening at the bottom. Afterward, dark materials are found to possibly extend along the axis of the expanded filament body. The MFE is analogous to large filament eruptions. However, a simultaneous observation of the Solar Dynamics Observatory shows that a jet is initiated and flows out along nearby coronal loops during the rising phase of the MFE. Meanwhile, small hot loops, which connect the original eruptive site of the minifilament to the footpoints of the coronal loops, are formed successively. A differential emission measure analysis demonstrates that, on the top of the new small loops, a hot cusp structure exists. We conjecture that the magnetic fields of the MFE interact with magnetic fields of the coronal loops. This interaction is interpreted as magnetic reconnection that produces the jet and the small hot loops.

  18. Coronal Structures as Tracers of Sub-Surface Processes

    Indian Academy of Sciences (India)

    tribpo

    dramatic differences in appearance and physical processes, all these structures share a common ... mena that indicate a close relationship between coronal and sub-photo- spheric processes. .... 8) maintaining the same chirality. Large scale ...

  19. Infrared Dual-Line Hanle Diagnostic of the Coronal Vector Magnetic Field

    Energy Technology Data Exchange (ETDEWEB)

    Dima, Gabriel I.; Kuhn, Jeffrey R. [Institute for Astronomy, University of Hawaii, Pukalani, HI (United States); Berdyugina, Svetlana V., E-mail: gdima@hawaii.edu [Institute for Astronomy, University of Hawaii, Pukalani, HI (United States); Kiepenheuer Institut fuer Sonnenphysik, Freiburg (Germany); Predictive Science Inc., San Diego, CA (United States)

    2016-04-20

    Measuring the coronal vector magnetic field is still a major challenge in solar physics. This is due to the intrinsic weakness of the field (e.g., ~4G at a height of 0.1R⊙ above an active region) and the large thermal broadening of coronal emission lines. We propose using concurrent linear polarization measurements of near-infrared forbidden and permitted lines together with Hanle effect models to calculate the coronal vector magnetic field. In the unsaturated Hanle regime both the direction and strength of the magnetic field affect the linear polarization, while in the saturated regime the polarization is insensitive to the strength of the field. The relatively long radiative lifetimes of coronal forbidden atomic transitions implies that the emission lines are formed in the saturated Hanle regime and the linear polarization is insensitive to the strength of the field. By combining measurements of both forbidden and permitted lines, the direction and strength of the field can be obtained. For example, the SiX 1.4301 μm line shows strong linear polarization and has been observed in emission over a large field-of-view (out to elongations of 0.5 R⊙). Here we describe an algorithm that combines linear polarization measurements of the SiX 1.4301 μm forbidden line with linear polarization observations of the HeI 1.0830 μm permitted coronal line to obtain the vector magnetic field. To illustrate the concept we assume that the emitting gas for both atomic transitions is located in the plane of the sky. The further development of this method and associated tools will be a critical step toward interpreting the high spectral, spatial and temporal infrared spectro-polarimetric measurements that will be possible when the Daniel K. Inouye Solar Telescope (DKIST) is completed in 2019.

  20. Frenkel-Charge-Transfer exciton intermixing theory for molecular crystals with two isolated Frenkel exciton states.

    Science.gov (United States)

    Bondarev, Igor; Popescu, Adrian

    We develop an analytical theory for the intra-intermolecular exciton intermixing in periodic 1D chains of planar organic molecules with two isolated low-lying Frenkel exciton states, typical of copper phthalocyanine (CuPc) and other transition metal phthalocyanine molecules. We formulate the Hamiltonian and use the exact Bogoliubov diagonalization procedure to derive the eigen energy spectrum for the two lowest intramolecular Frenkel excitons coupled to the intermolecular charge transfer (CT) exciton state. By comparing our theoretical spectrum with available experimental CuPc absorption data, we obtain the parameters of the Frenkel-CT exciton intermixing in CuPc thin films. The two Frenkel exciton states here are spaced apart by 0.26 eV, and the charge transfer exciton state is 50 meV above the lowest Frenkel exciton. Both Frenkel excitons are strongly mixed with the CT exciton, showing the coupling constant 0.17 eV in agreement with earlier electron transport experiments. Our results can be used for the proper interpretation of the physical properties of crystalline phthalocyanines. DOE-DE-SC0007117 (I.B.), UNC-GA ROI Grant (A.P.).

  1. Charge transfer in low-energy collisions of H with He+ and H+ with He in excited states

    Science.gov (United States)

    Loreau, J.; Ryabchenko, S.; Muñoz Burgos, J. M.; Vaeck, N.

    2018-04-01

    The charge transfer process in collisions of excited (n = 2, 3) hydrogen atoms with He+ and in collisions of excited helium atoms with H+ is studied theoretically. A combination of a fully quantum-mechanical method and a semi-classical approach is employed to calculate the charge-exchange cross sections at collision energies from 0.1 eV u‑1 up to 1 keV u‑1. These methods are based on accurate ab initio potential energy curves and non-adiabatic couplings for the molecular ion HeH+. Charge transfer can occur either in singlet or in triplet states, and the differences between the singlet and triplet spin manifolds are discussed. The dependence of the cross section on the quantum numbers n and l of the initial state is demonstrated. The isotope effect on the charge transfer cross sections, arising at low collision energy when H is substituted by D or T, is investigated. Rate coefficients are calculated for all isotopes up to 106 K. Finally, the impact of the present calculations on models of laboratory plasmas is discussed.

  2. The Three-part Structure of a Filament-unrelated Solar Coronal Mass Ejection

    Energy Technology Data Exchange (ETDEWEB)

    Song, H. Q.; Chen, Y.; Wang, B.; Li, B. [Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, and Institute of Space Sciences, Shandong University, Weihai, Shandong 264209 (China); Cheng, X. [School of Astronomy and Space Science, Nanjing University, Nanjing, Jiangsu 210093 (China); Zhang, J. [Department of Physics and Astronomy, George Mason University, Fairfax, VA 22030 (United States); Li, L. P. [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Hu, Q.; Li, G., E-mail: hqsong@sdu.edu.cn [Department of Space Science and CSPAR, University of Alabama in Huntsville, AL 35899 (United States)

    2017-10-10

    Coronal mass ejections (CMEs) often exhibit the typical three-part structure in the corona when observed with white-light coronagraphs, i.e., the bright leading front, dark cavity, and bright core, corresponding to a high-low-high density sequence. As CMEs result from eruptions of magnetic flux ropes (MFRs), which can possess either lower (e.g., coronal-cavity MFRs) or higher (e.g., hot-channel MFRs) density compared to their surroundings in the corona, the traditional opinion regards the three-part structure as the manifestations of coronal plasma pileup (high density), coronal-cavity MFR (low density), and filament (high density) contained in the trailing part of MFR, respectively. In this paper, we demonstrate that filament-unrelated CMEs can also exhibit the classical three-part structure. The observations were made from different perspectives through an event that occurred on 2011 October 4. The CME cavity corresponds to the low-density zone between the leading front and the high-density core, and it is obvious in the low corona and gradually becomes fuzzy when propagating outward. The bright core corresponds to a high-density structure that is suggested to be an erupting MFR. The MFR is recorded from both edge-on and face-on perspectives, exhibiting different morphologies that are due to projection effects. We stress that the zone (MFR) with lower (higher) density in comparison to the surroundings can appear as the dark cavity (bright core) when observed through white-light coronagraphs, which is not necessarily the coronal-cavity MFR (erupted filament).

  3. OBSERVATIONAL SIGNATURES OF CORONAL LOOP HEATING AND COOLING DRIVEN BY FOOTPOINT SHUFFLING

    Energy Technology Data Exchange (ETDEWEB)

    Dahlburg, R. B.; Taylor, B. D. [LCP and FD, Naval Research Laboratory, Washington, DC 20375 (United States); Einaudi, G. [Berkeley Research Associates, Inc., Beltsville, MD 20705 (United States); Ugarte-Urra, I. [College of Science, George Mason University, Fairfax, VA 22030 (United States); Warren, H. P. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Rappazzo, A. F. [Advanced Heliophysics, Pasadena, CA 91106 (United States); Velli, M., E-mail: rdahlbur@lcp.nrl.navy.mil [EPSS, UCLA, Los Angeles, CA 90095 (United States)

    2016-01-20

    The evolution of a coronal loop is studied by means of numerical simulations of the fully compressible three-dimensional magnetohydrodynamic equations using the HYPERION code. The footpoints of the loop magnetic field are advected by random motions. As a consequence, the magnetic field in the loop is energized and develops turbulent nonlinear dynamics characterized by the continuous formation and dissipation of field-aligned current sheets: energy is deposited at small scales where heating occurs. Dissipation is nonuniformly distributed so that only a fraction of the coronal mass and volume gets heated at any time. Temperature and density are highly structured at scales that, in the solar corona, remain observationally unresolved: the plasma of our simulated loop is multithermal, where highly dynamical hotter and cooler plasma strands are scattered throughout the loop at sub-observational scales. Numerical simulations of coronal loops of 50,000 km length and axial magnetic field intensities ranging from 0.01 to 0.04 T are presented. To connect these simulations to observations, we use the computed number densities and temperatures to synthesize the intensities expected in emission lines typically observed with the Extreme Ultraviolet Imaging Spectrometer on Hinode. These intensities are used to compute differential emission measure distributions using the Monte Carlo Markov Chain code, which are very similar to those derived from observations of solar active regions. We conclude that coronal heating is found to be strongly intermittent in space and time, with only small portions of the coronal loop being heated: in fact, at any given time, most of the corona is cooling down.

  4. The Three-part Structure of a Filament-unrelated Solar Coronal Mass Ejection

    International Nuclear Information System (INIS)

    Song, H. Q.; Chen, Y.; Wang, B.; Li, B.; Cheng, X.; Zhang, J.; Li, L. P.; Hu, Q.; Li, G.

    2017-01-01

    Coronal mass ejections (CMEs) often exhibit the typical three-part structure in the corona when observed with white-light coronagraphs, i.e., the bright leading front, dark cavity, and bright core, corresponding to a high-low-high density sequence. As CMEs result from eruptions of magnetic flux ropes (MFRs), which can possess either lower (e.g., coronal-cavity MFRs) or higher (e.g., hot-channel MFRs) density compared to their surroundings in the corona, the traditional opinion regards the three-part structure as the manifestations of coronal plasma pileup (high density), coronal-cavity MFR (low density), and filament (high density) contained in the trailing part of MFR, respectively. In this paper, we demonstrate that filament-unrelated CMEs can also exhibit the classical three-part structure. The observations were made from different perspectives through an event that occurred on 2011 October 4. The CME cavity corresponds to the low-density zone between the leading front and the high-density core, and it is obvious in the low corona and gradually becomes fuzzy when propagating outward. The bright core corresponds to a high-density structure that is suggested to be an erupting MFR. The MFR is recorded from both edge-on and face-on perspectives, exhibiting different morphologies that are due to projection effects. We stress that the zone (MFR) with lower (higher) density in comparison to the surroundings can appear as the dark cavity (bright core) when observed through white-light coronagraphs, which is not necessarily the coronal-cavity MFR (erupted filament).

  5. The Three-part Structure of a Filament-unrelated Solar Coronal Mass Ejection

    Science.gov (United States)

    Song, H. Q.; Cheng, X.; Chen, Y.; Zhang, J.; Wang, B.; Li, L. P.; Li, B.; Hu, Q.; Li, G.

    2017-10-01

    Coronal mass ejections (CMEs) often exhibit the typical three-part structure in the corona when observed with white-light coronagraphs, I.e., the bright leading front, dark cavity, and bright core, corresponding to a high-low-high density sequence. As CMEs result from eruptions of magnetic flux ropes (MFRs), which can possess either lower (e.g., coronal-cavity MFRs) or higher (e.g., hot-channel MFRs) density compared to their surroundings in the corona, the traditional opinion regards the three-part structure as the manifestations of coronal plasma pileup (high density), coronal-cavity MFR (low density), and filament (high density) contained in the trailing part of MFR, respectively. In this paper, we demonstrate that filament-unrelated CMEs can also exhibit the classical three-part structure. The observations were made from different perspectives through an event that occurred on 2011 October 4. The CME cavity corresponds to the low-density zone between the leading front and the high-density core, and it is obvious in the low corona and gradually becomes fuzzy when propagating outward. The bright core corresponds to a high-density structure that is suggested to be an erupting MFR. The MFR is recorded from both edge-on and face-on perspectives, exhibiting different morphologies that are due to projection effects. We stress that the zone (MFR) with lower (higher) density in comparison to the surroundings can appear as the dark cavity (bright core) when observed through white-light coronagraphs, which is not necessarily the coronal-cavity MFR (erupted filament).

  6. Comparison between two models of energy balance in coronal loops

    Science.gov (United States)

    Mac Cormack, C.; López Fuentes, M.; Vásquez, A. M.; Nuevo, F. A.; Frazin, R. A.; Landi, E.

    2017-10-01

    In this work we compare two models to analyze the energy balance along coronal magnetic loops. For the first stationary model we deduce an expression of the energy balance along the loops expressed in terms of quantities provided by the combination of differential emission measure tomography (DEMT) applied to EUV images time series and potential extrapolations of the coronal magnetic field. The second applied model is a 0D hydrodynamic model that provides the evolution of the average properties of the coronal plasma along the loops, using as input parameters the loop length and the heating rate obtained with the first model. We compare the models for two Carrington rotations (CR) corresponding to different periods of activity: CR 2081, corresponding to a period of minimum activity observed with the Extreme Ultraviolet Imager (EUVI) on board of the Solar Terrestrial Relations Observatory (STEREO), and CR 2099, corresponding to a period of activity increase observed with the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO). The results of the models are consistent for both rotations.

  7. Evolving Coronal Holes and Interplanetary Erupting Stream ...

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... Coronal holes and interplanetary disturbances are important aspects of the physics of the Sun and heliosphere. Interplanetary disturbances are identified as an increase in the density turbulence compared with the ambient solar wind. Erupting stream disturbances are transient large-scale structures of ...

  8. GUIDING NONLINEAR FORCE-FREE MODELING USING CORONAL OBSERVATIONS: FIRST RESULTS USING A QUASI-GRAD-RUBIN SCHEME

    Energy Technology Data Exchange (ETDEWEB)

    Malanushenko, A. [Department of Physics, Montana State University, Bozeman, MT (United States); Schrijver, C. J.; DeRosa, M. L. [Lockheed Martin Advanced Technology Center, Palo Alto, CA (United States); Wheatland, M. S.; Gilchrist, S. A. [Sydney Institute for Astronomy, School of Physics, University of Sydney (Australia)

    2012-09-10

    At present, many models of the coronal magnetic field rely on photospheric vector magnetograms, but these data have been shown to be problematic as the sole boundary information for nonlinear force-free field extrapolations. Magnetic fields in the corona manifest themselves in high-energy images (X-rays and EUV) in the shapes of coronal loops, providing an additional constraint that is not at present used as constraints in the computational domain, directly influencing the evolution of the model. This is in part due to the mathematical complications of incorporating such input into numerical models. Projection effects, confusion due to overlapping loops (the coronal plasma is optically thin), and the limited number of usable loops further complicate the use of information from coronal images. We develop and test a new algorithm to use images of coronal loops in the modeling of the solar coronal magnetic field. We first fit projected field lines with those of constant-{alpha} force-free fields to approximate the three-dimensional distribution of currents in the corona along a sparse set of trajectories. We then apply a Grad-Rubin-like iterative technique, which uses these trajectories as volume constraints on the values of {alpha}, to obtain a volume-filling nonlinear force-free model of the magnetic field, modifying a code and method presented by Wheatland. We thoroughly test the technique on known analytical and solar-like model magnetic fields previously used for comparing different extrapolation techniques and compare the results with those obtained by currently available methods relying only on the photospheric data. We conclude that we have developed a functioning method of modeling the coronal magnetic field by combining the line-of-sight component of the photospheric magnetic field with information from coronal images. Whereas we focus on the use of coronal loop information in combination with line-of-sight magnetograms, the method is readily extended to

  9. GUIDING NONLINEAR FORCE-FREE MODELING USING CORONAL OBSERVATIONS: FIRST RESULTS USING A QUASI-GRAD-RUBIN SCHEME

    International Nuclear Information System (INIS)

    Malanushenko, A.; Schrijver, C. J.; DeRosa, M. L.; Wheatland, M. S.; Gilchrist, S. A.

    2012-01-01

    At present, many models of the coronal magnetic field rely on photospheric vector magnetograms, but these data have been shown to be problematic as the sole boundary information for nonlinear force-free field extrapolations. Magnetic fields in the corona manifest themselves in high-energy images (X-rays and EUV) in the shapes of coronal loops, providing an additional constraint that is not at present used as constraints in the computational domain, directly influencing the evolution of the model. This is in part due to the mathematical complications of incorporating such input into numerical models. Projection effects, confusion due to overlapping loops (the coronal plasma is optically thin), and the limited number of usable loops further complicate the use of information from coronal images. We develop and test a new algorithm to use images of coronal loops in the modeling of the solar coronal magnetic field. We first fit projected field lines with those of constant-α force-free fields to approximate the three-dimensional distribution of currents in the corona along a sparse set of trajectories. We then apply a Grad-Rubin-like iterative technique, which uses these trajectories as volume constraints on the values of α, to obtain a volume-filling nonlinear force-free model of the magnetic field, modifying a code and method presented by Wheatland. We thoroughly test the technique on known analytical and solar-like model magnetic fields previously used for comparing different extrapolation techniques and compare the results with those obtained by currently available methods relying only on the photospheric data. We conclude that we have developed a functioning method of modeling the coronal magnetic field by combining the line-of-sight component of the photospheric magnetic field with information from coronal images. Whereas we focus on the use of coronal loop information in combination with line-of-sight magnetograms, the method is readily extended to incorporate

  10. Interplanetary Coronal Mass Ejections detected by HAWC

    Science.gov (United States)

    Lara, Alejandro

    The High Altitude Water Cherenkov (HAWC) observatory is being constructed at the volcano Sierra Negra (4100 m a.s.l.) in Mexico. HAWC’s primary purpose is the study of both: galactic and extra-galactic sources of high energy gamma rays. HAWC will consist of 300 large water Cherenkov detectors (WCD), instrumented with 1200 photo-multipliers. The Data taking has already started while construction continues, with the completion projected for late 2014. The HAWC counting rate will be sensitive to cosmic rays with energies above the geomagnetic cutoff of the site (˜ 8 GV). In particular, HAWC will detect solar energetic particles known as Ground Level Enhancements (GLEs), and the effects of Coronal Mass Ejections on the galactic cosmic ray flux, known as Forbush Decreases. In this paper, we present a description of the instrument and its response to interplanetary coronal mass ejections, and other solar wind large scale structures, observed during the August-December 2013 period.

  11. Solar Coronal Jets: Observations, Theory, and Modeling

    Science.gov (United States)

    Raouafi, N. E.; Patsourakos, S.; Pariat, E.; Young, P. R.; Sterling, A.; Savcheva, A.; Shimojo, M.; Moreno-Insertis, F.; Devore, C. R.; Archontis, V.; hide

    2016-01-01

    Chromospheric and coronal jets represent important manifestations of ubiquitous solar transients, which may be the source of signicant mass and energy input to the upper solar atmosphere and the solar wind. While the energy involved in a jet-like event is smaller than that of nominal solar ares and Coronal Mass Ejections (CMEs), jets share many common properties with these major phenomena, in particular, the explosive magnetically driven dynamics. Studies of jets could, therefore, provide critical insight for understanding the larger, more complex drivers of the solar activity. On the other side of the size-spectrum, the study of jets could also supply important clues on the physics of transients closeor at the limit of the current spatial resolution such as spicules. Furthermore, jet phenomena may hint to basic process for heating the corona and accelerating the solar wind; consequently their study gives us the opportunity to attack a broadrange of solar-heliospheric problems.

  12. Sinonasal polyposis: investigation by direct coronal CT

    International Nuclear Information System (INIS)

    Drutman, J.; Harnsberger, H.R.; Babbel, R.W.; Sonkens, J.W.; Braby, D.

    1994-01-01

    To demonstrate the typical clinical and CT features of sinonasal polyposis, we reviewed the clinical records and preoperative direct coronal CT scans of 35 patients with surgically proven disease. Symptoms included progressive nasal stuffiness (100 %), rhinorrhea (69 %), facial pain (60 %), headache (43 %) and anosmia (17 %). We found associations with rhinitis (46 %), asthma (29 %) and aspirin sensitivity (9 %). Coronal CT features included polypoid masses in the nasal cavity (91 %), partial or complete pansinus opacification (90 %), enlargement of infundibula (89 %), bony attenuation of the ethmoid trabeculae (63 %) and nasal septum (37 %), opacified ethmoid sinuses with convex lateral walls (51 %) and air-fluid levels (43 %). The latter feature correlated with symptoms and signs of acute sinusitis in only 40 % of patients. Recognition of sinonasal polyposis is important to the endoscopic surgeon since it can be the most troubling sinonasal inflammatory disease to manage due to its aggressive nature and tendency to recur despite appropriate treatment. (orig.)

  13. Glauber amplitudes for transitions from low lying states in hydrogen atom by charged particle impact

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, S; Srivastava, M K [Roorkee Univ. (India). Dept. of Physics

    1977-07-01

    The Glauber amplitudes for the general transition nlm ..-->.. n'1'm' in charged particle - hydrogen atom collisions have been obtained in the form of a one-dimensional integral. The final expression involves only a few hypergeometric functions if n is not too large and is particularly suited to study excitation to highly excited states from a low lying state.

  14. submitter BREIT code: Analytical solution of the balance rate equations for charge-state evolutions of heavy-ion beams in matter

    CERN Document Server

    Winckler, N; Shevelko, V P; Al-Turany, M; Kollegger, T; Stöhlker, Th

    2017-01-01

    A detailed description of a recently developed BREIT computer code (Balance Rate Equations of Ion Transportation) for calculating charge-state fractions of ion beams passing through matter is presented. The code is based on the analytical solutions of the differential balance equations for the charge-state fractions as a function of the target thickness and can be used for calculating the ion evolutions in gaseous, solid and plasma targets. The BREIT code is available on-line and requires the charge-changing cross sections and initial conditions in the input file. The eigenvalue decomposition method, applied to obtain the analytical solutions of the rate equations, is described in the paper. Calculations of non-equilibrium and equilibrium charge-state fractions, performed by the BREIT code, are compared with experimental data and results of other codes for ion beams in gaseous and solid targets. Ability and limitations of the BREIT code are discussed in detail.

  15. Charge-state distributions of 100, 175, 275, and 352 MeV gold ions emerging from thin carbon foils

    International Nuclear Information System (INIS)

    Martin, J.A.; Auble, R.L.; Erb, K.A.; Jones, C.M.; Olsen, D.K.

    1985-01-01

    These measurements were undertaken as a consequence of our failure early this year to accelerate Au +46 ions in the Oak Ridge Isochronous Cyclotron using an injected beam of 352 MeV 197 Au +17 from the 25 MV tandem accelerator. Following that unsuccessful test, we made a preliminary measurement of the charge-state distribution of 352 MeV 197 Au ions emerging from a carbon foil using the bending magnet that is a part of the cyclotron beam injection system. The measured mean charge was approx.38.5, about 4.5 charge-states lower than predicted by the Sayer semi-empirical formula. The measurements reported here were done more precisely and systematically confirm that preliminary result. 12 refs., 5 figs., 4 tabs

  16. Charge-state distributions of 100, 175, 275, and 352 MeV gold ions emerging from thin carbon foils

    Energy Technology Data Exchange (ETDEWEB)

    Martin, J.A.; Auble, R.L.; Erb, K.A.; Jones, C.M.; Olsen, D.K.

    1985-01-01

    These measurements were undertaken as a consequence of our failure early this year to accelerate Au/sup +46/ ions in the Oak Ridge Isochronous Cyclotron using an injected beam of 352 MeV /sup 197/Au/sup +17/ from the 25 MV tandem accelerator. Following that unsuccessful test, we made a preliminary measurement of the charge-state distribution of 352 MeV /sup 197/Au ions emerging from a carbon foil using the bending magnet that is a part of the cyclotron beam injection system. The measured mean charge was approx.38.5, about 4.5 charge-states lower than predicted by the Sayer semi-empirical formula. The measurements reported here were done more precisely and systematically confirm that preliminary result. 12 refs., 5 figs., 4 tabs.

  17. Charge sensitive amplifies. The state of arts

    Energy Technology Data Exchange (ETDEWEB)

    Mori, Kunishiro [Clear Pulse Co., Tokyo (Japan)

    1996-07-01

    In the radiation detectors, signals are essentially brought with charges produced by radiation, then it is naturally the best way to use a charge sensitive amplifier (CSA) system to extract those signals. The CSA is thought to be the best amplifier suitable to almost all the radiation detectors, if neglecting economical points of view. The CSA has been only applied to special fields like radiation detection because the concept of `charges` is not so universal against the concepts of `voltage` and `current`. The CSA, however, is low in noise and a high speed amplifier and may be applicable not only to radiation measurement but also piezoelectric devices and also bolometers. In this article, noise in the CSA, basic circuit on the CSA, concepts of `equivalent noise charge` (ENC), a method for the ENC, and importance of the `open-loop gain` in the CSA to achieve better performance of it and how to realize in a practical CSA were described. And, characteristics on a counting rate of the CSA, various circuit used in the CSA, and CSAs which are commercially available at present and special purpose CSAs were also introduced. (G.K.)

  18. PROJECTION EFFECTS IN CORONAL DIMMINGS AND ASSOCIATED EUV WAVE EVENT

    Energy Technology Data Exchange (ETDEWEB)

    Dissauer, K.; Temmer, M.; Veronig, A. M.; Vanninathan, K. [IGAM/Institute of Physics, University of Graz, Universitätsplatz 5/II, A-8010 Graz (Austria); Magdalenić, J., E-mail: karin.dissauer@uni-graz.at [Solar-Terrestrial Center of Excellence-SIDC, Royal Observatory of Belgium, Av. Circulaire 3, B-1180 Brussels (Belgium)

    2016-10-20

    We investigate the high-speed ( v > 1000 km s{sup −1}) extreme-ultraviolet (EUV) wave associated with an X1.2 flare and coronal mass ejection (CME) from NOAA active region 11283 on 2011 September 6 (SOL2011-09-06T22:12). This EUV wave features peculiar on-disk signatures; in particular, we observe an intermittent “disappearance” of the front for 120 s in Solar Dynamics Observatory ( SDO )/AIA 171, 193, 211 Å data, whereas the 335 Å filter, sensitive to hotter plasmas ( T ∼ 2.5 MK), shows a continuous evolution of the wave front. The eruption was also accompanied by localized coronal dimming regions. We exploit the multi-point quadrature position of SDO and STEREO-A , to make a thorough analysis of the EUV wave evolution, with respect to its kinematics and amplitude evolution and reconstruct the SDO line-of-sight (LOS) direction of the identified coronal dimming regions in STEREO-A . We show that the observed intensities of the dimming regions in SDO /AIA depend on the structures that are lying along their LOS and are the combination of their individual intensities, e.g., the expanding CME body, the enhanced EUV wave, and the CME front. In this context, we conclude that the intermittent disappearance of the EUV wave in the AIA 171, 193, and 211 Å filters, which are channels sensitive to plasma with temperatures below ∼2 MK is also caused by such LOS integration effects. These observations clearly demonstrate that single-view image data provide us with limited insight to correctly interpret coronal features.

  19. Ab initio modeling of excitonic and charge-transfer states in organic semiconductors: the PTB1/PCBM low band gap system.

    Science.gov (United States)

    Borges, Itamar; Aquino, Adélia J A; Köhn, Andreas; Nieman, Reed; Hase, William L; Chen, Lin X; Lischka, Hans

    2013-12-11

    A detailed quantum chemical simulation of the excitonic and charge-transfer (CT) states of a bulk heterojunction model containing poly(thieno[3,4-b]thiophene benzodithiophene) (PTB1)/[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) is reported. The largest molecular model contains two stacked PTB1 trimer chains interacting with C60 positioned on top of and lateral to the (PTB1)3 stack. The calculations were performed using the algebraic diagrammatic construction method to second order (ADC(2)). One main result of the calculations is that the CT states are located below the bright inter-chain excitonic state, directly accessible via internal conversion processes. The other important aspects of the calculations are the formation of discrete bands of CT states originating from the lateral C60's and the importance of inter-chain charge delocalization for the stability of the CT states. A simple model for the charge separation step is also given, revealing the energetic feasibility of the overall photovoltaic process.

  20. Quantitative analysis of charge trapping and classification of sub-gap states in MoS2 TFT by pulse I-V method

    Science.gov (United States)

    Park, Junghak; Hur, Ji-Hyun; Jeon, Sanghun

    2018-04-01

    The threshold voltage instabilities and huge hysteresis of MoS2 thin film transistors (TFTs) have raised concerns about their practical applicability in next-generation switching devices. These behaviors are associated with charge trapping, which stems from tunneling to the adjacent trap site, interfacial redox reaction and interface and/or bulk trap states. In this report, we present quantitative analysis on the electron charge trapping mechanism of MoS2 TFT by fast pulse I-V method and the space charge limited current (SCLC) measurement. By adopting the fast pulse I-V method, we were able to obtain effective mobility. In addition, the origin of the trap states was identified by disassembling the sub-gap states into interface trap and bulk trap states by simple extraction analysis. These measurement methods and analyses enable not only quantitative extraction of various traps but also an understanding of the charge transport mechanism in MoS2 TFTs. The fast I-V data and SCLC data obtained under various measurement temperatures and ambient show that electron transport to neighboring trap sites by tunneling is the main charge trapping mechanism in thin-MoS2 TFTs. This implies that interfacial traps account for most of the total sub-gap states while the bulk trap contribution is negligible, at approximately 0.40% and 0.26% in air and vacuum ambient, respectively. Thus, control of the interface trap states is crucial to further improve the performance of devices with thin channels.

  1. Reconstructed frontal and coronal cuts in computed tomography of the trunk

    International Nuclear Information System (INIS)

    Fochem, K.; Klumair, J.

    1982-01-01

    A comparison between the original coronally cuts and the reconstructed coronal cuts yielded basic information on the loss of quality by computed reconstruction of images. As for the trunk, only comparisons between the conventional linear tomography and computed frontal of trunk cuts are possible. A few examples will demonstrate that despite a considerable loss of quality, computed frontal cuts will supply additional information in certain cases. It is also shown that the reconstructed frontal cuts cannot replace conventional tomography. (orig.) [de

  2. Rydberg-state reionization of multiply charged ions escaping from solid surfaces

    International Nuclear Information System (INIS)

    Nedeljkovic, Lj.D.; Nedeljkovic, N.N.

    2003-01-01

    Reionization rates of Rydberg states (n>>1 and l=0, 1, and 2) of multiply charged ionic projectiles escaping solid surfaces are calculated. These rates are obtained in an analytic form as a function of the ion-surface distance R. A phenomenological model of the reionization process, based on two-state quantum dynamics, is adopted for the vicinity of the potential barrier top. The results of calculations show that ionization rates for different Rydberg states are strictly localized and relatively separated. Universality of the reionization rate as a function of the scaling parameter α, describing the turning point configurations, is demonstrated. The reionization is discussed within the framework of a nonresonant population-reionization process at intermediate ionic velocities (v∼1 a.u.). The influence of reionization on the population of ionic Rydberg states is expressed in terms of a renormalized neutralization rate. It is demonstrated that the reionization effect significantly changes the population curves for all Rydberg states. The population curves obtained correlate with beam-foil experimental data concerning the S VI, Cl VII, and Ar VIII ions

  3. Non-adversarial justice and the coroner's court: a proposed therapeutic, restorative, problem-solving model.

    Science.gov (United States)

    King, Michael S

    2008-12-01

    Increasingly courts are using new approaches that promote a more comprehensive resolution of legal problems, minimise any negative effects that legal processes have on participant wellbeing and/or that use legal processes to promote participant wellbeing. Therapeutic jurisprudence, restorative justice, mediation and problem-solving courts are examples. This article suggests a model for the use of these processes in the coroner's court to minimise negative effects of coroner's court processes on the bereaved and to promote a more comprehensive resolution of matters at issue, including the determination of the cause of death and the public health and safety promotion role of the coroner.

  4. Fragile charge order in the nonsuperconducting ground state of the underdoped high-temperature superconductors.

    Science.gov (United States)

    Tan, B S; Harrison, N; Zhu, Z; Balakirev, F; Ramshaw, B J; Srivastava, A; Sabok-Sayr, S A; Sabok, S A; Dabrowski, B; Lonzarich, G G; Sebastian, Suchitra E

    2015-08-04

    The normal state in the hole underdoped copper oxide superconductors has proven to be a source of mystery for decades. The measurement of a small Fermi surface by quantum oscillations on suppression of superconductivity by high applied magnetic fields, together with complementary spectroscopic measurements in the hole underdoped copper oxide superconductors, point to a nodal electron pocket from charge order in YBa2Cu3(6+δ). Here, we report quantum oscillation measurements in the closely related stoichiometric material YBa2Cu4O8, which reveals similar Fermi surface properties to YBa2Cu3(6+δ), despite the nonobservation of charge order signatures in the same spectroscopic techniques, such as X-ray diffraction, that revealed signatures of charge order in YBa2Cu3(6+δ). Fermi surface reconstruction in YBa2Cu4O8 is suggested to occur from magnetic field enhancement of charge order that is rendered fragile in zero magnetic fields because of its potential unconventional nature and/or its occurrence as a subsidiary to more robust underlying electronic correlations.

  5. Adaptive state-of-charge indication system for a Li-ion battery-powered devices

    NARCIS (Netherlands)

    Pop, V.; Danilov, D.; Bergveld, H.J.; Notten, P.H.L.; Regtien, P.P.L.

    2006-01-01

    Accurate State-of-Charge (SoC) and remammg run-time indication for portable devices is important for the user convenience and to prolong the lifetime of batteries. So far, no one succeeded in coming up with a SoC system that is accurate enough under all realistic user conditions. An algorithm that

  6. Observable Signatures of Energy Release in Braided Coronal Loops

    Energy Technology Data Exchange (ETDEWEB)

    Pontin, D. I. [University of Dundee, Nethergate, Dundee, DD1 4HN (United Kingdom); Janvier, M. [Institut d’Astrophysique Spatiale, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Bât. 121, F-91405, Orsay Cedex (France); Tiwari, S. K.; Winebarger, A. R.; Cirtain, J. W. [NASA Marshall Space Flight Center, ZP 13, Huntsville, AL 35812 (United States); Galsgaard, K. [Niels Bohr Institute, Geological Museum Østervoldgade 5-7, DK-1350, Copenhagen K (Denmark)

    2017-03-10

    We examine the turbulent relaxation of solar coronal loops containing non-trivial field line braiding. Such field line tangling in the corona has long been postulated in the context of coronal heating models. We focus on the observational signatures of energy release in such braided magnetic structures using MHD simulations and forward modeling tools. The aim is to answer the following question: if energy release occurs in a coronal loop containing braided magnetic flux, should we expect a clearly observable signature in emissions? We demonstrate that the presence of braided magnetic field lines does not guarantee a braided appearance to the observed intensities. Observed intensities may—but need not necessarily—reveal the underlying braided nature of the magnetic field, depending on the degree and pattern of the field line tangling within the loop. However, in all cases considered, the evolution of the braided loop is accompanied by localized heating regions as the loop relaxes. Factors that may influence the observational signatures are discussed. Recent high-resolution observations from Hi-C have claimed the first direct evidence of braided magnetic fields in the corona. Here we show that both the Hi-C data and some of our simulations give the appearance of braiding at a range of scales.

  7. Density Fluctuations in a Polar Coronal Hole

    Science.gov (United States)

    Hahn, Michael; D’Huys, Elke; Savin, Daniel Wolf

    2018-06-01

    We have measured the root-mean-square (rms) amplitude of intensity fluctuations, ΔI, in plume and interplume regions of a polar coronal hole. These intensity fluctuations correspond to density fluctuations. Using data from the Sun Watcher using the Active Pixel System detector and Image Processing on the Project for Onboard Autonomy (Proba2), our results extend up to a height of about 1.35 R ⊙. One advantage of the rms analysis is that it does not rely on a detailed evaluation of the power spectrum, which is limited by noise levels to low heights in the corona. The rms approach can be performed up to larger heights where the noise level is greater, provided that the noise itself can be quantified. At low heights, both the absolute ΔI, and the amplitude relative to the mean intensity, ΔI/I, decrease with height. However, starting at about 1.2 R ⊙, ΔI/I increases, reaching 20%–40% by 1.35 R ⊙. This corresponds to density fluctuations of Δn e/n e ≈ 10%–20%. The increasing relative amplitude implies that the density fluctuations are generated in the corona itself. One possibility is that the density fluctuations are generated by an instability of Alfvén waves. This generation mechanism is consistent with some theoretical models and with observations of Alfvén wave amplitudes in coronal holes. Although we find that the energy of the observed density fluctuations is small, these fluctuations are likely to play an important indirect role in coronal heating by promoting the reflection of Alfvén waves and driving turbulence.

  8. THE NATURE OF CME-FLARE-ASSOCIATED CORONAL DIMMING

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, J. X. [Key Laboratory of Planetary Sciences, Shanghai Astronomical Observatory, Shanghai 200030 (China); Qiu, J., E-mail: chengjx@shao.ac.cn [Department of Physics, Montana State University, Bozeman MT 59717-3840 (United States)

    2016-07-01

    Coronal mass ejections (CMEs) are often accompanied by coronal dimming that is evident in extreme ultraviolet (EUV) and soft X-ray observations. The locations of dimming are sometimes considered to map footpoints of the erupting flux rope. As the emitting material expands in the corona, the decreased plasma density leads to reduced emission observed in spectral and irradiance measurements. Therefore, signatures of dimming may reflect the properties of CMEs in the early phase of their eruption. In this study, we analyze the event of flare, CME, and coronal dimming on 2011 December 26. We use the data from the Atmospheric Imaging Assembly on the Solar Dynamics Observatory for disk observations of the dimming, and analyze images taken by EUVI, COR1, and COR2 on board the Solar Terrestrial Relations Observatory to obtain the height and velocity of the associated CMEs observed at the limb. We also measure the magnetic reconnection rate from flare observations. Dimming occurs in a few locations next to the flare ribbons, and it is observed in multiple EUV passbands. Rapid dimming starts after the onset of fast reconnection and CME acceleration, and its evolution tracks the CME height and flare reconnection. The spatial distribution of dimming exhibits cores of deep dimming with a rapid growth, and their light curves are approximately linearly scaled with the CME height profile. From the dimming analysis we infer the process of the CME expansion, and estimate properties of the CME.

  9. THE NATURE OF CME-FLARE-ASSOCIATED CORONAL DIMMING

    International Nuclear Information System (INIS)

    Cheng, J. X.; Qiu, J.

    2016-01-01

    Coronal mass ejections (CMEs) are often accompanied by coronal dimming that is evident in extreme ultraviolet (EUV) and soft X-ray observations. The locations of dimming are sometimes considered to map footpoints of the erupting flux rope. As the emitting material expands in the corona, the decreased plasma density leads to reduced emission observed in spectral and irradiance measurements. Therefore, signatures of dimming may reflect the properties of CMEs in the early phase of their eruption. In this study, we analyze the event of flare, CME, and coronal dimming on 2011 December 26. We use the data from the Atmospheric Imaging Assembly on the Solar Dynamics Observatory for disk observations of the dimming, and analyze images taken by EUVI, COR1, and COR2 on board the Solar Terrestrial Relations Observatory to obtain the height and velocity of the associated CMEs observed at the limb. We also measure the magnetic reconnection rate from flare observations. Dimming occurs in a few locations next to the flare ribbons, and it is observed in multiple EUV passbands. Rapid dimming starts after the onset of fast reconnection and CME acceleration, and its evolution tracks the CME height and flare reconnection. The spatial distribution of dimming exhibits cores of deep dimming with a rapid growth, and their light curves are approximately linearly scaled with the CME height profile. From the dimming analysis we infer the process of the CME expansion, and estimate properties of the CME.

  10. Charge exchange and ionization in atom-multiply-charged ion collisions

    International Nuclear Information System (INIS)

    Presnyakov, L.P.; Uskov, D.B.

    1988-01-01

    This study investigates one-electron transitions to the continuous and discrete spectra induced by a collision of atom A and multiply-charged ion B +Z with nuclear charge Z > 3. An analytical method is developed the charge-exchange reaction; this method is a generalization of the decay model and the approximation of nonadiabatic coupling of two states that are used as limiting cases in the proposed approach

  11. Coronal 2D MR cholangiography overestimates the length of the right hepatic duct in liver transplantation donors

    International Nuclear Information System (INIS)

    Kim, Bohyun; Kim, Kyoung Won; Kim, So Yeon; Park, So Hyun; Lee, Jeongjin; Song, Gi Won; Jung, Dong-Hwan; Ha, Tae-Yong; Lee, Sung Gyu

    2017-01-01

    To compare the length of the right hepatic duct (RHD) measured on rotatory coronal 2D MR cholangiography (MRC), rotatory axial 2D MRC, and reconstructed 3D MRC. Sixty-seven donors underwent coronal and axial 2D projection MRC and 3D MRC. RHD length was measured and categorized as ultrashort (≤1 mm), short (>1-14 mm), and long (>14 mm). The measured length, frequency of overestimation, and the degree of underestimation between two 2D MRC sets were compared to 3D MRC. The length of the RHD from 3D MRC, coronal 2D MRC, and axial 2D MRC showed significant difference (p < 0.05). RHD was frequently overestimated on the coronal than on axial 2D MRC (61.2 % vs. 9 %; p <.0001). On coronal 2D MRC, four (6 %) with short RHD and one (1.5 %) with ultrashort RHD were over-categorized as long RHD. On axial 2D MRC, overestimation was mostly <1 mm (83.3 %), none exceeding 3 mm or over-categorized. The degree of underestimation between the two projection planes was comparable. Coronal 2D MRC overestimates the RHD in liver donors. We suggest adding axial 2D MRC to conventional coronal 2D MRC in the preoperative workup protocol for living liver donors to avoid unexpected confrontation with multiple ductal openings when harvesting the graft. (orig.)

  12. Coronal 2D MR cholangiography overestimates the length of the right hepatic duct in liver transplantation donors

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bohyun [University of Ulsan College of Medicine, Department of Radiology, Asan Medical Center, 88, Olympic-ro 43-gil, Songpa-gu, Seoul (Korea, Republic of); Ajou University School of Medicine, Department of Radiology, Ajou University Medical Center, Suwon (Korea, Republic of); Kim, Kyoung Won; Kim, So Yeon; Park, So Hyun [University of Ulsan College of Medicine, Department of Radiology, Asan Medical Center, 88, Olympic-ro 43-gil, Songpa-gu, Seoul (Korea, Republic of); Lee, Jeongjin [Soongsil University, School of Computer Science and Engineering, Seoul (Korea, Republic of); Song, Gi Won; Jung, Dong-Hwan; Ha, Tae-Yong; Lee, Sung Gyu [University of Ulsan College of Medicine, Department of Surgery, Division of Hepatobiliary and Liver Transplantation Surgery, Asan Medical Center, Seoul (Korea, Republic of)

    2017-05-15

    To compare the length of the right hepatic duct (RHD) measured on rotatory coronal 2D MR cholangiography (MRC), rotatory axial 2D MRC, and reconstructed 3D MRC. Sixty-seven donors underwent coronal and axial 2D projection MRC and 3D MRC. RHD length was measured and categorized as ultrashort (≤1 mm), short (>1-14 mm), and long (>14 mm). The measured length, frequency of overestimation, and the degree of underestimation between two 2D MRC sets were compared to 3D MRC. The length of the RHD from 3D MRC, coronal 2D MRC, and axial 2D MRC showed significant difference (p < 0.05). RHD was frequently overestimated on the coronal than on axial 2D MRC (61.2 % vs. 9 %; p <.0001). On coronal 2D MRC, four (6 %) with short RHD and one (1.5 %) with ultrashort RHD were over-categorized as long RHD. On axial 2D MRC, overestimation was mostly <1 mm (83.3 %), none exceeding 3 mm or over-categorized. The degree of underestimation between the two projection planes was comparable. Coronal 2D MRC overestimates the RHD in liver donors. We suggest adding axial 2D MRC to conventional coronal 2D MRC in the preoperative workup protocol for living liver donors to avoid unexpected confrontation with multiple ductal openings when harvesting the graft. (orig.)

  13. Coronal reconstruction of unenhanced abdominal CT for correct ureteral stone size classification

    Energy Technology Data Exchange (ETDEWEB)

    Berkovitz, Nadav; Simanovsky, Natalia; Hiller, Nurith [Hadassah Mount Scopus - Hebrew University Medical Center, Department of Radiology, Jerusalem (Israel); Katz, Ran [Hadassah Mount Scopus - Hebrew University Medical Center, Department of Urology, Jerusalem (Israel); Salama, Shaden [Hadassah Mount Scopus - Hebrew University Medical Center, Department of Emergency Medicine, Jerusalem (Israel)

    2010-05-15

    To determine whether size measurement of a urinary calculus in coronal reconstruction of computed tomography (CT) differs from stone size measured in the axial plane, and whether the difference alters clinical decision making. We retrospectively reviewed unenhanced CT examinations of 150 patients admitted to the emergency room (ER) with acute renal colic. Maximal ureteral calculus size was measured on axial slices and coronal reconstructions. Clinical significance was defined as an upgrading or downgrading of stone size according to accepted thresholds of treatment: {<=}5 mm, 6-9 mm and {>=}10 mm. There were 151 stones in 150 patients (male:female 115:34, mean age 41 years). Transverse stone diameters ranged from 1 to 11 mm (mean 4 mm). On coronal images, 56 (37%) stones were upgraded in severity; 46 (30%) from below 5 mm to 6 mm or more, and ten (7%) from 6-9 mm to 10 mm or more. Transverse measurement on the axial slices enabled correct categorization of 95 stones (63%). Transverse calculus measurement on axial slices often underestimates stone size and provides incorrect clinical classification of the true maximal stone diameter. Coronal reconstruction provides additional information in patients with renal colic that may alter treatment strategy. (orig.)

  14. Coronal reconstruction of unenhanced abdominal CT for correct ureteral stone size classification

    International Nuclear Information System (INIS)

    Berkovitz, Nadav; Simanovsky, Natalia; Hiller, Nurith; Katz, Ran; Salama, Shaden

    2010-01-01

    To determine whether size measurement of a urinary calculus in coronal reconstruction of computed tomography (CT) differs from stone size measured in the axial plane, and whether the difference alters clinical decision making. We retrospectively reviewed unenhanced CT examinations of 150 patients admitted to the emergency room (ER) with acute renal colic. Maximal ureteral calculus size was measured on axial slices and coronal reconstructions. Clinical significance was defined as an upgrading or downgrading of stone size according to accepted thresholds of treatment: ≤5 mm, 6-9 mm and ≥10 mm. There were 151 stones in 150 patients (male:female 115:34, mean age 41 years). Transverse stone diameters ranged from 1 to 11 mm (mean 4 mm). On coronal images, 56 (37%) stones were upgraded in severity; 46 (30%) from below 5 mm to 6 mm or more, and ten (7%) from 6-9 mm to 10 mm or more. Transverse measurement on the axial slices enabled correct categorization of 95 stones (63%). Transverse calculus measurement on axial slices often underestimates stone size and provides incorrect clinical classification of the true maximal stone diameter. Coronal reconstruction provides additional information in patients with renal colic that may alter treatment strategy. (orig.)

  15. Root canal adhesive filling in dogs' teeth with or without coronal restoration: a histopathological evaluation.

    Science.gov (United States)

    Leonardo, Mario Roberto; Barnett, Frederick; Debelian, Gilberto J; de Pontes Lima, Regina Karla; Bezerra da Silva, Léa Assed

    2007-11-01

    The purpose of this study was to evaluate in vivo the response of the periradicular tissues after endodontic treatment and root filling with Epiphany/Resilon (Penntron Clinical Technologies, LLC, Wallingford, CT) or gutta percha and new Sealapex (SybronEndo, Glendora, CA) in dogs' teeth with or without coronal restoration. Teeth without coronal restorations were used to assess the influence of continuous exposure to the oral environment on the periradicular tissues. Sixty root canals with vital pulps in three dogs were instrumented and obturated in a single session and randomly assigned to one of four groups as follows. group 1: root canal filling with Epiphany/Resilon with coronal restoration, group 2: root canal filling with Sealapex sealer and gutta percha with restoration, group 3: root canal filling with Epiphany/Resilon without restoration, and group 4: root canal filling with Sealapex sealer and gutta percha without coronal restoration. After 90 days, the animals were euthanized, and the maxillas and mandibles were removed and submitted for histologic processing. Longitudinal sections were obtained and stained with hematoxylin and eosin, Mallory's trichrome, and Brown and Brenn stains and examined under light microscopy. There were significant differences found between the four groups (p < 0.05). The results showed that roots canals filled with Epiphany/Resilon, with coronal restoration, had significantly less periradicular inflammation than roots canals filled with gutta percha and Sealapex, with coronal restoration (p = 0.021). No significant difference was observed in the intensity of inflammation between roots canals filled with Epiphany/Resilon with no restoration and roots filled with gutta percha and Sealapex with restoration (p = 0.269). Roots canals filled with gutta percha and Sealapex sealer without coronal restoration showed the greatest degree of periradicular inflammation.

  16. ON THE RELATIONSHIP BETWEEN THE CORONAL MAGNETIC DECAY INDEX AND CORONAL MASS EJECTION SPEED

    Energy Technology Data Exchange (ETDEWEB)

    Xu Yan; Liu Chang; Jing Ju; Wang Haimin, E-mail: yx2@njit.edu [Space Weather Research Lab, Center for Solar-Terrestrial Research, New Jersey Institute of Technology, 323 Martin Luther King Boulevard, Newark, NJ 07102-1982 (United States)

    2012-12-10

    Numerical simulations suggest that kink and torus instabilities are two potential contributors to the initiation and prorogation of eruptive events. A magnetic parameter called the decay index (i.e., the coronal magnetic gradient of the overlying fields above the eruptive flux ropes) could play an important role in controlling the kinematics of eruptions. Previous studies have identified a threshold range of the decay index that distinguishes between eruptive and confined configurations. Here we advance the study by investigating if there is a clear correlation between the decay index and coronal mass ejection (CME) speed. Thirty-eight CMEs associated with filament eruptions and/or two-ribbon flares are selected using the H{alpha} data from the Global H{alpha} Network. The filaments and flare ribbons observed in H{alpha} associated with the CMEs help to locate the magnetic polarity inversion line, along which the decay index is calculated based on the potential field extrapolation using Michelson Doppler Imager magnetograms as boundary conditions. The speeds of CMEs are obtained from the LASCO C2 CME catalog available online. We find that the mean decay index increases with CME speed for those CMEs with a speed below 1000 km s{sup -1} and stays flat around 2.2 for the CMEs with higher speeds. In addition, we present a case study of a partial filament eruption, in which the decay indices show different values above the erupted/non-erupted part.

  17. CORONAL AND CHROMOSPHERIC SIGNATURES OF LARGE-SCALE DISTURBANCES ASSOCIATED WITH A MAJOR SOLAR ERUPTION

    International Nuclear Information System (INIS)

    Zong, Weiguo; Dai, Yu

    2015-01-01

    We present both coronal and chromospheric observations of large-scale disturbances associated with a major solar eruption on 2005 September 7. In the Geostationary Operational Environmental Satellites/Solar X-ray Imager (SXI), arclike coronal brightenings are recorded propagating in the southern hemisphere. The SXI front shows an initially constant speed of 730 km s −1 and decelerates later on, and its center is near the central position angle of the associated coronal mass ejection (CME) but away from the flare site. Chromospheric signatures of the disturbances are observed in both Mauna Loa Solar Observatory (MLSO)/Polarimeter for Inner Coronal Studies Hα and MLSO/Chromospheric Helium I Imaging Photometer He i λ10830 and can be divided into two parts. The southern signatures occur in regions where the SXI front sweeps over, with the Hα bright front coincident with the SXI front, while the He i dark front lags the SXI front but shows a similar kinematics. Ahead of the path of the southern signatures, oscillations of a filament are observed. The northern signatures occur near the equator, with the Hα and He i fronts coincident with each other. They first propagate westward and then deflect to the north at the boundary of an equatorial coronal hole. Based on these observational facts, we suggest that the global disturbances are associated with the CME lift-off and show a hybrid nature: a mainly non-wave CME flank nature for the SXI signatures and the corresponding southern chromospheric signatures, and a shocked fast-mode coronal MHD wave nature for the northern chromospheric signatures

  18. CORONAL AND CHROMOSPHERIC SIGNATURES OF LARGE-SCALE DISTURBANCES ASSOCIATED WITH A MAJOR SOLAR ERUPTION

    Energy Technology Data Exchange (ETDEWEB)

    Zong, Weiguo [Key Laboratory of Space Weather, National Center for Space Weather, China Meteorological Administration, Beijing 100081 (China); Dai, Yu, E-mail: ydai@nju.edu.cn [Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, Nanjing 210023 (China)

    2015-08-20

    We present both coronal and chromospheric observations of large-scale disturbances associated with a major solar eruption on 2005 September 7. In the Geostationary Operational Environmental Satellites/Solar X-ray Imager (SXI), arclike coronal brightenings are recorded propagating in the southern hemisphere. The SXI front shows an initially constant speed of 730 km s{sup −1} and decelerates later on, and its center is near the central position angle of the associated coronal mass ejection (CME) but away from the flare site. Chromospheric signatures of the disturbances are observed in both Mauna Loa Solar Observatory (MLSO)/Polarimeter for Inner Coronal Studies Hα and MLSO/Chromospheric Helium I Imaging Photometer He i λ10830 and can be divided into two parts. The southern signatures occur in regions where the SXI front sweeps over, with the Hα bright front coincident with the SXI front, while the He i dark front lags the SXI front but shows a similar kinematics. Ahead of the path of the southern signatures, oscillations of a filament are observed. The northern signatures occur near the equator, with the Hα and He i fronts coincident with each other. They first propagate westward and then deflect to the north at the boundary of an equatorial coronal hole. Based on these observational facts, we suggest that the global disturbances are associated with the CME lift-off and show a hybrid nature: a mainly non-wave CME flank nature for the SXI signatures and the corresponding southern chromospheric signatures, and a shocked fast-mode coronal MHD wave nature for the northern chromospheric signatures.

  19. The angle of inclination of the native ACL in the coronal and sagittal planes.

    Science.gov (United States)

    Reid, Jonathan C; Yonke, Bret; Tompkins, Marc

    2017-04-01

    The purpose of this cross-sectional study was to evaluate the angle of inclination of the native anterior cruciate ligament (ACL) in both the sagittal and coronal planes and to evaluate these findings based on sex, height, BMI, and skeletal maturity. Inclusion criteria for the study included patients undergoing routine magnetic resonance imaging (MRI) of the knee at a single outpatient orthopedic center who had an intact ACL on MRI. Measurements of the angle of inclination were made on MRIs in both the sagittal and coronal planes. Patients were compared based on sex, height, BMI, and skeletal maturity. One-hundred and eighty-eight patients were included (36 skeletally immature/152 skeletally mature; 98 male/90 female). The overall angle of inclination was 74.3° ± 4.8° in the coronal plane and 46.9° ± 4.9° in the sagittal plane. Skeletally immature patients (coronal: 71.8° ± 6.1°; sagittal: 44.7° ± 5.5°) were significantly different in both coronal and sagittal planes (P = 0.04 and 0.01, respectively) from skeletally mature patients (coronal: 75.3° ± 4.7°; sagittal: 47.4° ± 4.7°). There were no differences based on sex, height, or BMI. There are differences between the angle of inclination findings in this study and other studies, which could be due to MRI and measurement techniques. Clinically, skeletal maturity may be important to account for when using the ACL angle of inclination to evaluate anatomic ACL reconstruction. Prognostic retrospective study, Level of evidence III.

  20. Tooth coronal index: Key for age estimation on digital panoramic radiographs

    Directory of Open Access Journals (Sweden)

    Ravleen Nagi

    2018-01-01

    Full Text Available Background: Assessment of age through teeth is one of the most reliable and simple method than skeletal remains, to calculate age of an individual. Objectives: The study was carried out with an aim to evaluate reliability of dental age assessment through tooth coronal index (TCI method. Materials and Methods: The digital panoramic radiographs of 100 subjects of Chhattisgarh aged 20–70 years were selected for the study. The measurements were performed on the JPEG images of selected panoramic radiographs by using Adobe Acrobat 7.0 professional software. The height of the crown, i.e., coronal height, and the height of the coronal pulp cavity, i.e., coronal pulp cavity height, of mandibular second premolars and first molars were measured in millimeter (mm and then TCI was calculated for each tooth. Actual age of a subject was compared with TCI of tooth and the acquired data were subjected to Pearson's correlation and unpaired t-tests. Results: Negative correlation was observed between the real age and TCI of mandibular first molar (r = −0.092, P = 0.365 and second premolar (r = −0.168, P = 0.096. Statistically significant difference was observed between real age and TCI for mandibular second premolar and first molar (P = 0.000 by unpaired t-test. Conclusion: TCI has the potential to estimate age of an individual on dental radiographs. It is simple, cost effective than histological methods and can be applied to both living and unknown dead.

  1. Role of Magnetic Carpet in Coronal Heating

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... One of the fundamental questions in solar physics is how the solar corona maintains its high temperature of several million Kelvin above photosphere with a temperature of 6000 K. Observations show that solar coronal heating problem is highly complex with many different facts. It is likely that different ...

  2. Mechanisms of Coronal Heating S. R. Verma

    Indian Academy of Sciences (India)

    Abstract. The Sun is a mysterious star. The high temperature of the chromosphere and corona present one of the most puzzling problems of solar physics. Observations show that the solar coronal heating problem is highly complex with many different facts. It is likely that different heating mechanisms are at work in solar ...

  3. Effect of trap states and microstructure on charge carrier conduction mechanism through semicrystalline poly(vinyl alcohol) granular film

    Science.gov (United States)

    Das, A. K.; Bhowmik, R. N.; Meikap, A. K.

    2018-05-01

    We report a comprehensive study on hysteresis behaviour of current-voltage characteristic and impedance spectroscopy of granular semicrystalline poly(vinyl alcohol) (PVA) film. The charge carrier conduction mechanism and charge traps of granular PVA film by measuring and analyzing the temperature dependent current-voltage characteristic indicate a bi-stable electronic state in the film. A sharp transformation of charge carrier conduction mechanism from Poole-Frenkel emission to space charge limited current mechanism has been observed. An anomalous oscillatory behaviour of current has been observed due to electric pulse effect on the molecular chain of the polymer. Effect of microstructure on charge transport mechanism has been investigated from impedance spectroscopy analysis. An equivalent circuit model has been proposed to explain the result.

  4. A combination Kalman filter approach for State of Charge estimation of lithium-ion battery considering model uncertainty

    International Nuclear Information System (INIS)

    Li, Yanwen; Wang, Chao; Gong, Jinfeng

    2016-01-01

    An accurate battery State of Charge estimation plays an important role in battery electric vehicles. This paper makes two contributions to the existing literature. (1) A recursive least squares method with fuzzy adaptive forgetting factor has been presented to update the model parameters close to the real value more quickly. (2) The statistical information of the innovation sequence obeying chi-square distribution has been introduced to identify model uncertainty, and a novel combination algorithm of strong tracking unscented Kalman filter and adaptive unscented Kalman filter has been developed to estimate SOC (State of Charge). Experimental results indicate that the novel algorithm has a good performance in estimating the battery SOC against initial SOC errors and voltage sensor drift. A comparison with the unscented Kalman filter-based algorithms and adaptive unscented Kalman filter-based algorithms shows that the proposed SOC estimation method has better accuracy, robustness and convergence behavior. - Highlights: • Recursive least squares method with fuzzy adaptive forgetting factor is presented. • The innovation obeying chi-square distribution is used to identify uncertainty. • A combination Karman filter approach for State of Charge estimation is presented. • The performance of the proposed method is verified by comparison results.

  5. Required Critical Conversations Between Medical Examiners/Coroners and Forensic Nurses.

    Science.gov (United States)

    Infanti Mraz, Megan A

    2016-01-01

    Forensic teams work with the deceased and their families on a daily basis. The forensic team fulfills an important role during the death process and serves as a medium between the medical community and investigative community. The medical examiner, or coroner, depending on jurisdiction, plays a critical role in the death investigation, whose assessments and findings are a key element in care for the deceased in relation to the investigation. Communication regarding care for the deceased is critical to the completion of the investigation. Nine key discussion points are addressed as a means to launch communications between the forensic team and the medical examiner/coroner's office.

  6. Charge-state distribution in close collisions of 3 MeV C2+ ions with Ag and Au atoms

    NARCIS (Netherlands)

    Boerma, D.O; Arnoldbik, W.M.; Kabachnik, N.M.; Khodyrev, V.A.

    The charge-state distributions of 3 MeV carbon ions scattered over angles of 40 degrees and 60 degrees from sub-monolayers of Ag and Au atoms evaporated on a substrate and from thick layers of Ag and Au have been measured. A close similarity of the charge distributions in all cases is interpreted as

  7. Thermal and electrodynamical formation mechanisms of overloaded AC states and charging rate influence on their stable dynamics

    International Nuclear Information System (INIS)

    Romanovskii, V.; Watanabe, K.; Awaji, S.

    2013-01-01

    Highlights: •Overloaded AC states are investigated to understand the mechanisms of there formation. •There exist characteristic time windows defining the existence of stable overloaded AC states. •Limiting values of the electric field, current and temperature are higher than the quench ones. -- Abstract: The macroscopic thermal and electrodynamical phenomena occurring in high-T c superconductors during overloaded AC states are theoretically investigated to understand the basic physical mechanisms, which are characteristic for the stable formation of the operating modes when the peak current exceeds the critical current of a superconductor during AC modes. It is shown that there exist characteristic time windows defining the existence of stable overloaded AC states. They identify the stability boundary of the overloaded AC states. Therefore, there is the maximum allowable value of a peak current of stable overloaded AC regimes at the given charging rate, cooling conditions and properties of a superconductor and a matrix. The results obtained prove that the limiting peak current is higher than the corresponding quench current defining the stability margin of DC states. It monotonically increases with the charging rate. Besides, in the stable overloaded AC states, the peak values of the electric field and temperature may be also noticeably higher than the corresponding quench values. They depend on the peak current and charging rate at the given cooling conditions. As a result, high-T c superconducting tapes can stably work under intensive AC modes without instability onset when the peak of applied currents may significantly exceed not only the critical current but also the corresponding values of DC-quench currents

  8. Excitation and damping of transversal oscillation in coronal loops by wake phenomena

    Directory of Open Access Journals (Sweden)

    A abedini

    2018-02-01

    Full Text Available Transversal oscillation of coronal loops that are interpreted as signatures of magneto hydrodynamics (MHD waves are observed frequently in active region corona loops. The amplitude of this oscillation has been found to be strongly attenuated. The damping of transverse oscillation may be produced by the dissipation mechanism and the wake of the traveling disturbance. The damping of transversal loop oscillations with wake phenomena is not related to any dissipation mechanism. Also, these kinds of coronal loop oscillations are not related to the kink mode, although this mode can be occurred after the attenuation process by the energy of the wave packet deposited in the loop.  In this paper the excitation and damping of transversal coronal loop oscillations with wake of traveling wave packet is discussed in detail, both theoretically and observationally. Here, the transversal coronal loop oscillations is modeled with a one dimensional simple line-tied. The dynamics of the loop and the coronal is governed by the Klein–Gordon differential equation. A localized disturbance that can be generated by nearby flare produces a perturbation that undergoes dispersion as it propagates toward the loop. As a consequence, the amplitudes of oscillates decay with time roughly t-1/2 at the external cutoff frequency. These observed data on 2016-Dec-4 by Atmospheric Imaging Assembly (AIA onboard Solar Dynamic Observatory (SDO observations data, consisting of 560 images with an interval of 24 seconds in the 171 A0 pass band is analyzed for evidence of excitation and damping of transverse oscillations of coronal loop that is situated near a flare. In this analyzed signatures of transverse oscillations that are damped rapidly were found, with periods in the range of P=18.5-23.85 minutes. Furthermore, oscillation of loop segments attenuate with time roughly as t-α that average values of α for 4 different loops change form 0.65-0.80. The magnitude values of α are in

  9. Rapid Estimation Method for State of Charge of Lithium-Ion Battery Based on Fractional Continual Variable Order Model

    Directory of Open Access Journals (Sweden)

    Xin Lu

    2018-03-01

    Full Text Available In recent years, the fractional order model has been employed to state of charge (SOC estimation. The non integer differentiation order being expressed as a function of recursive factors defining the fractality of charge distribution on porous electrodes. The battery SOC affects the fractal dimension of charge distribution, therefore the order of the fractional order model varies with the SOC at the same condition. This paper proposes a new method to estimate the SOC. A fractional continuous variable order model is used to characterize the fractal morphology of charge distribution. The order identification results showed that there is a stable monotonic relationship between the fractional order and the SOC after the battery inner electrochemical reaction reaches balanced. This feature makes the proposed model particularly suitable for SOC estimation when the battery is in the resting state. Moreover, a fast iterative method based on the proposed model is introduced for SOC estimation. The experimental results showed that the proposed iterative method can quickly estimate the SOC by several iterations while maintaining high estimation accuracy.

  10. How to construct self/anti-self charge conjugate states?

    International Nuclear Information System (INIS)

    Dvoeglazov, V V

    2014-01-01

    We construct self/anti–self charge conjugate (Majorana–like) states for the (1/2, 0)⊕(0, 1/2) representation of the Lorentz group, and their analogs for higher spins within the quantum field theory. The problem of the basis rotations and that of the selection of phases in the Dirac–like and Majorana–like field operators are considered. The discrete symmetries properties (P, C, T) are studied. The corresponding dynamical equations are presented. In the (1/2, 0) ⊕ (0, 1/2) representation they obey the Dirac–like equation with eight components, which has been first introduced by Markov. Thus, the Fock space for corresponding quantum fields is doubled (as shown by Ziino). The particular attention has been paid to the questions of chirality and helicity (two concepts which are frequently confused in the literature) for Dirac and Majorana states. We further review several experimental consequences which follow from the previous works of M. Kirchbach et al. on neutrinoless double beta decay, and G. J. Ni et al. on meson lifetimes

  11. Battery state-of-charge estimation using approximate least squares

    Science.gov (United States)

    Unterrieder, C.; Zhang, C.; Lunglmayr, M.; Priewasser, R.; Marsili, S.; Huemer, M.

    2015-03-01

    In recent years, much effort has been spent to extend the runtime of battery-powered electronic applications. In order to improve the utilization of the available cell capacity, high precision estimation approaches for battery-specific parameters are needed. In this work, an approximate least squares estimation scheme is proposed for the estimation of the battery state-of-charge (SoC). The SoC is determined based on the prediction of the battery's electromotive force. The proposed approach allows for an improved re-initialization of the Coulomb counting (CC) based SoC estimation method. Experimental results for an implementation of the estimation scheme on a fuel gauge system on chip are illustrated. Implementation details and design guidelines are presented. The performance of the presented concept is evaluated for realistic operating conditions (temperature effects, aging, standby current, etc.). For the considered test case of a GSM/UMTS load current pattern of a mobile phone, the proposed method is able to re-initialize the CC-method with a high accuracy, while state-of-the-art methods fail to perform a re-initialization.

  12. Radio and white-light observations of coronal transients

    International Nuclear Information System (INIS)

    Dulk, G.A.

    1980-01-01

    Optical, radio and X-ray evidence of violent mass motions in the corona has existed for some years but only recently have the form, nature, frequency and implication of the transients become obvious. The author reviews the observed properties of coronal transients, concentrating on the white-light and radio manifestations. The classification according to speeds seems to be meaningful, with the slow transients having thermal emissions at radio wavelengths and the fast ones non-thermal. The possible mechanisms involved in the radio bursts are discussed and the estimates of various forms of energy are reviewed. It appears that the magnetic energy transported from the Sun by the transient exceeds that of any other form, and that magnetic forces dominate in the dynamics of the motions. The conversion of magnetic energy into mechanical energy, by expansion of the fields, provides a possible driving force for the coronal and interplanetary shock waves. (Auth.)

  13. Prediction of coronal structure of the solar eclipse of October 23, 1976

    International Nuclear Information System (INIS)

    Schatten, K.H.

    1976-01-01

    Earlier work on the prediction of solar eclipse coronal structures is briefly summarised. A computer drawn plot made on October 18 1976 showed the field time structure predicted for the time of the solar eclipse on October 23. A very dipolar coronal field was indicated, and a very large equatorial streamer was predicted for both the east and west limbs of the Sun, due to the lack of very strong active regions near either limb. Nested coronal arches were seen within this equatorial streamer, and many small arches were also seen on both limbs. The main feature, however, is the prediction of the two large bright streamers marking the solar equator, with polar plumes in a characteristic dipole fashion. At the time of the eclipse it is hoped that a high resolution photograph will allow much of the structure to be discovered. (U.K.)

  14. Long-lived charge-separated states in ligand-stabilized silver clusters

    KAUST Repository

    Pelton, Matthew; Tang, Yun; Bakr, Osman; Stellacci, Francesco

    2012-01-01

    Recently developed synthesis methods allow for the production of atomically monodisperse clusters of silver atoms stabilized in solution by aromatic thiol ligands, which exhibit intense absorption peaks throughout the visible and near-IR spectral regions. Here we investigated the time-dependent optical properties of these clusters. We observed two kinetic processes following ultrafast laser excitation of any of the absorption peaks: a rapid decay, with a time constant of 1 ps or less, and a slow decay, with a time constant that can be longer than 300 ns. Both time constants decrease as the polarity of the solvent increases, indicating that the two processes correspond to the formation and recombination, respectively, of a charge-separated state. The long lifetime of this state and the broad optical absorption spectrum mean that the ligand-stabilized silver clusters are promising materials for solar energy harvesting. © 2012 American Chemical Society.

  15. Long-lived charge-separated states in ligand-stabilized silver clusters

    KAUST Repository

    Pelton, Matthew

    2012-07-25

    Recently developed synthesis methods allow for the production of atomically monodisperse clusters of silver atoms stabilized in solution by aromatic thiol ligands, which exhibit intense absorption peaks throughout the visible and near-IR spectral regions. Here we investigated the time-dependent optical properties of these clusters. We observed two kinetic processes following ultrafast laser excitation of any of the absorption peaks: a rapid decay, with a time constant of 1 ps or less, and a slow decay, with a time constant that can be longer than 300 ns. Both time constants decrease as the polarity of the solvent increases, indicating that the two processes correspond to the formation and recombination, respectively, of a charge-separated state. The long lifetime of this state and the broad optical absorption spectrum mean that the ligand-stabilized silver clusters are promising materials for solar energy harvesting. © 2012 American Chemical Society.

  16. Shear-induced opening of the coronal magnetic field

    Science.gov (United States)

    Wolfson, Richard

    1995-01-01

    This work describes the evolution of a model solar corona in response to motions of the footpoints of its magnetic field. The mathematics involved is semianalytic, with the only numerical solution being that of an ordinary differential equation. This approach, while lacking the flexibility and physical details of full MHD simulations, allows for very rapid computation along with complete and rigorous exploration of the model's implications. We find that the model coronal field bulges upward, at first slowly and then more dramatically, in response to footpoint displacements. The energy in the field rises monotonically from that of the initial potential state, and the field configuration and energy appraoch asymptotically that of a fully open field. Concurrently, electric currents develop and concentrate into a current sheet as the limiting case of the open field is approached. Examination of the equations shows rigorously that in the asymptotic limit of the fully open field, the current layer becomes a true ideal MHD singularity.

  17. Coronal mass ejections, interplanetary shocks in relation with forbush decreases associated with intense geomagnetic storms

    International Nuclear Information System (INIS)

    Verma, P L; Patel, Nand Kumar; Prajapati, Mateswari

    2014-01-01

    Coronal mass ejections (CMEs} are the most energetic solar events in which large amount of solar plasma materials are ejected from the sun into heliosphere, causing major disturbances in solar wind plasma, Interplanetary shocks, Forbush decrease(Fds) in cosmic ray intensity and geomagnetic storms. We have studied Forbush decreases associated with intense geomagnetic storms observed at Oulu super neutron monitor, during the period of May 1998-Dec 2006 with coronal mass ejections (CMEs), X-ray solar flares and interplanetary shocks. We have found that all the (100%) Forbush decreases associated with intense geomagnetic storms are associated with halo and partial halo coronal mass ejections (CMEs). The association rate between halo and partial halo coronal mass ejections are found 96.00%and 04.00% respectively. Most of the Forbush decreases associated with intense geomagnetic storms (96.29%) are associated with X-ray solar flares of different categories . The association rates for X-Class, M-Class, and C- Class X -ray solar flares are found 34.62%, 50.00% and 15.38% respectively .Further we have concluded that majority of the Forbush decrease associated with intense geomagnetic storms are related to interplanetary shocks (92.30 %) and the related shocks are forward shocks. We have found positive co-relation with co-relation co-efficient .7025 between magnitudes of Forbush decreases associated with intense geomagnetic storms and speed of associated coronal mass ejections. Positive co-relation with co-relation co-efficient 0.48 has also been found between magnitudes of intense geomagnetic storms and speed of associated coronal mass ejections.

  18. Coronal mass ejections and their sheath regions in interplanetary space

    Science.gov (United States)

    Kilpua, Emilia; Koskinen, Hannu E. J.; Pulkkinen, Tuija I.

    2017-11-01

    Interplanetary coronal mass ejections (ICMEs) are large-scale heliospheric transients that originate from the Sun. When an ICME is sufficiently faster than the preceding solar wind, a shock wave develops ahead of the ICME. The turbulent region between the shock and the ICME is called the sheath region. ICMEs and their sheaths and shocks are all interesting structures from the fundamental plasma physics viewpoint. They are also key drivers of space weather disturbances in the heliosphere and planetary environments. ICME-driven shock waves can accelerate charged particles to high energies. Sheaths and ICMEs drive practically all intense geospace storms at the Earth, and they can also affect dramatically the planetary radiation environments and atmospheres. This review focuses on the current understanding of observational signatures and properties of ICMEs and the associated sheath regions based on five decades of studies. In addition, we discuss modelling of ICMEs and many fundamental outstanding questions on their origin, evolution and effects, largely due to the limitations of single spacecraft observations of these macro-scale structures. We also present current understanding of space weather consequences of these large-scale solar wind structures, including effects at the other Solar System planets and exoplanets. We specially emphasize the different origin, properties and consequences of the sheaths and ICMEs.

  19. Coronal mass ejections and their sheath regions in interplanetary space

    Directory of Open Access Journals (Sweden)

    Emilia Kilpua

    2017-11-01

    Full Text Available Abstract Interplanetary coronal mass ejections (ICMEs are large-scale heliospheric transients that originate from the Sun. When an ICME is sufficiently faster than the preceding solar wind, a shock wave develops ahead of the ICME. The turbulent region between the shock and the ICME is called the sheath region. ICMEs and their sheaths and shocks are all interesting structures from the fundamental plasma physics viewpoint. They are also key drivers of space weather disturbances in the heliosphere and planetary environments. ICME-driven shock waves can accelerate charged particles to high energies. Sheaths and ICMEs drive practically all intense geospace storms at the Earth, and they can also affect dramatically the planetary radiation environments and atmospheres. This review focuses on the current understanding of observational signatures and properties of ICMEs and the associated sheath regions based on five decades of studies. In addition, we discuss modelling of ICMEs and many fundamental outstanding questions on their origin, evolution and effects, largely due to the limitations of single spacecraft observations of these macro-scale structures. We also present current understanding of space weather consequences of these large-scale solar wind structures, including effects at the other Solar System planets and exoplanets. We specially emphasize the different origin, properties and consequences of the sheaths and ICMEs.

  20. Charged state distributions of swift heavy ions behind various solid targets (36 ≤ Zp ≤ 92, 18 MeV/u ≤ E ≤ 44 MeV/u)

    International Nuclear Information System (INIS)

    Leon, A.; Melki, S.; Lisfi, D.; Grandin, J.P.; Jardin, P.; Suraud, M.G.; Cassimi, A.

    1998-01-01

    Noting the lack of and the increasing need for information concerning heavy ion stripping in the intermediate velocity regime, the authors have studied a large number of ion-target systems experimentally. They present experimental charge state distributions obtained at the GANIL accelerator for several projectiles (36 ≤ Z p ≤ 92) with energies ranging from 18 MeV/u to 44 MeV/u, emerging from various target foils (4 ≤ Z t ≤ 79) of natural isotopic composition. The target thicknesses (from 1 microg/cm 2 up to several mg/cm 2 ) are chosen to cover the pre- and post-charge-state equilibrium regimes. Charge state fractions, mean charge state, charge distribution width, and emerging ion energy are tabulated for each of the 107 projectile-target element-target thickness combinations. They also present an improvement of the semi-empirical formulae proposed by Baron et al. to predict the mean charge states and the distribution widths at equilibrium. These formulae are compared with the available experimental data

  1. BAYESIAN MAGNETOHYDRODYNAMIC SEISMOLOGY OF CORONAL LOOPS

    International Nuclear Information System (INIS)

    Arregui, I.; Asensio Ramos, A.

    2011-01-01

    We perform a Bayesian parameter inference in the context of resonantly damped transverse coronal loop oscillations. The forward problem is solved in terms of parametric results for kink waves in one-dimensional flux tubes in the thin tube and thin boundary approximations. For the inverse problem, we adopt a Bayesian approach to infer the most probable values of the relevant parameters, for given observed periods and damping times, and to extract their confidence levels. The posterior probability distribution functions are obtained by means of Markov Chain Monte Carlo simulations, incorporating observed uncertainties in a consistent manner. We find well-localized solutions in the posterior probability distribution functions for two of the three parameters of interest, namely the Alfven travel time and the transverse inhomogeneity length scale. The obtained estimates for the Alfven travel time are consistent with previous inversion results, but the method enables us to additionally constrain the transverse inhomogeneity length scale and to estimate real error bars for each parameter. When observational estimates for the density contrast are used, the method enables us to fully constrain the three parameters of interest. These results can serve to improve our current estimates of unknown physical parameters in coronal loops and to test the assumed theoretical model.

  2. A model for radio emission from solar coronal shocks

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, G. Q.; Chen, L.; Wu, D. J., E-mail: djwu@pmo.ac.cn [Purple Mountain Observatory, CAS, Nanjing 210008 (China)

    2014-05-01

    Solar coronal shocks are very common phenomena in the solar atmosphere and are believed to be the drivers of solar type II radio bursts. However, the microphysical nature of these emissions is still an open question. This paper proposes that electron cyclotron maser (ECM) emission is responsible for the generation of radiation from the coronal shocks. In the present model, an energetic ion beam accelerated by the shock first excites the Alfvén wave (AW), then the excited AW leads to the formation of a density-depleted duct along the foreshock boundary of the shock. In this density-depleted duct, the energetic electron beam produced via the shock acceleration can effectively excite radio emission by ECM instability. Our results show that this model may potentially be applied to solar type II radio bursts.

  3. A model for radio emission from solar coronal shocks

    International Nuclear Information System (INIS)

    Zhao, G. Q.; Chen, L.; Wu, D. J.

    2014-01-01

    Solar coronal shocks are very common phenomena in the solar atmosphere and are believed to be the drivers of solar type II radio bursts. However, the microphysical nature of these emissions is still an open question. This paper proposes that electron cyclotron maser (ECM) emission is responsible for the generation of radiation from the coronal shocks. In the present model, an energetic ion beam accelerated by the shock first excites the Alfvén wave (AW), then the excited AW leads to the formation of a density-depleted duct along the foreshock boundary of the shock. In this density-depleted duct, the energetic electron beam produced via the shock acceleration can effectively excite radio emission by ECM instability. Our results show that this model may potentially be applied to solar type II radio bursts.

  4. Coronal and Intraradicular Appearances Affect Radiographic Perception of the Periapical Region.

    Science.gov (United States)

    Strong, Julie W; Woodmansey, Karl F; Khademi, John A; Hatton, John F

    2017-05-01

    The influence of the radiographic appearances of the coronal and intraradicular areas on periapical radiographic interpretation has been minimally evaluated in dentistry and endodontics. The purpose of this study was to evaluate the effects that the coronal and intraradicular radiographic appearance has on endodontists' radiographic interpretations of periapical areas. In a split-group study design using an online survey format, 2 pairs of digital periapical radiographic images were evaluated by 2 groups (A and B) of endodontist readers for the presence of a periapical finding. The images in each pair were identical except that 1 image of each image pairs had coronal restorations and/or root canal fillings altered using Adobe Photoshop software (Adobe Systems, San Jose, CA). The periapical areas were not altered. Using a 5-point Likert scale, the endodontist readers were asked to "Please evaluate the periapical area(s)." A Mann-Whitney U test was used to statistically evaluate the difference between the groups. Significance was set at P < .01. There were 417 readers in group A and 442 readers in group B. The Mann-Whitney U test showed a significant difference in the responses between the groups for both image pairs (P < .01). Because the periapical areas of the image pairs were unaltered, the differing coronal and intraradicular areas of the radiographs appear to have influenced endodontists' interpretations of the periapical areas. This finding has implications for all radiographic outcome assessments. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  5. Model of charge-state distributions for electron cyclotron resonance ion source plasmas

    Directory of Open Access Journals (Sweden)

    D. H. Edgell

    1999-12-01

    Full Text Available A computer model for the ion charge-state distribution (CSD in an electron cyclotron resonance ion source (ECRIS plasma is presented that incorporates non-Maxwellian distribution functions, multiple atomic species, and ion confinement due to the ambipolar potential well that arises from confinement of the electron cyclotron resonance (ECR heated electrons. Atomic processes incorporated into the model include multiple ionization and multiple charge exchange with rate coefficients calculated for non-Maxwellian electron distributions. The electron distribution function is calculated using a Fokker-Planck code with an ECR heating term. This eliminates the electron temperature as an arbitrary user input. The model produces results that are a good match to CSD data from the ANL-ECRII ECRIS. Extending the model to 1D axial will also allow the model to determine the plasma and electrostatic potential profiles, further eliminating arbitrary user input to the model.

  6. RADIOLOGICAL TIPS Coronal views of the paediatric mandibular ...

    African Journals Online (AJOL)

    imaging. None of the cases subsequently revealed any evidence of traumatic brain injury on CTB but they all demonstrated mandibular condyle fractures best appreciated on coronal views. Axial (Fig. 1) ... T Peedikayil, MB ChB. Department of Radiology, Red Cross War Memorial Children's Hospital, Cape Town.

  7. Low to High Spin-State Transition Induced by Charge Ordering in Antiferromagnetic YBaCo2O5

    International Nuclear Information System (INIS)

    Vogt, T.; Woodward, P. M.; Karen, P.; Hunter, B. A.; Henning, P.; Moodenbaugh, A. R.

    2000-01-01

    The oxygen-deficient double perovskite YBaCo 2 O 5 , containing corner-linked CoO 5 square pyramids as principal building units, undergoes a paramagnetic to antiferromagnetic spin ordering at 330 K. This is accompanied by a tetragonal to orthorhombic distortion. Below 220 K orbital ordering and long-range Co 2+ /Co 3+ charge ordering occur as well as a change in the Co 2+ spin state from low to high spin. This transition is shown to be very sensitive to the oxygen content of the sample. To our knowledge this is the first observation of a spin-state transition induced by long-range orbital and charge ordering. (c) 2000 The American Physical Society

  8. “Dandelion” Filament Eruption and Coronal Waves Associated with a Solar Flare on 2011 February 16

    International Nuclear Information System (INIS)

    Cabezas, Denis P.; Ishitsuka, Mutsumi; Ishitsuka, José K.; Martínez, Lurdes M.; Buleje, Yovanny J.; Morita, Satoshi; Asai, Ayumi; UeNo, Satoru; Ishii, Takako T.; Kitai, Reizaburo; Takasao, Shinsuke; Yoshinaga, Yusuke; Otsuji, Kenichi; Shibata, Kazunari

    2017-01-01

    Coronal disturbances associated with solar flares, such as H α Moreton waves, X-ray waves, and extreme ultraviolet (EUV) coronal waves, are discussed herein in relation to magnetohydrodynamic fast-mode waves or shocks in the corona. To understand the mechanism of coronal disturbances, full-disk solar observations with high spatial and temporal resolution over multiple wavelengths are of crucial importance. We observed a filament eruption, whose shape is like a “dandelion,” associated with the M1.6 flare that occurred on 2011 February 16 in H α images taken by the Flare Monitoring Telescope at Ica University, Peru. We derive the three-dimensional velocity field of the erupting filament. We also identify winking filaments that are located far from the flare site in the H α images, whereas no Moreton wave is observed. By comparing the temporal evolution of the winking filaments with those of the coronal wave seen in the EUV images data taken by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory and by the Extreme Ultraviolet Imager on board the Solar Terrestrial Relations Observatory-Ahead , we confirm that the winking filaments were activated by the EUV coronal wave.

  9. “Dandelion” Filament Eruption and Coronal Waves Associated with a Solar Flare on 2011 February 16

    Energy Technology Data Exchange (ETDEWEB)

    Cabezas, Denis P.; Ishitsuka, Mutsumi; Ishitsuka, José K. [Geophysical Institute of Peru, Calle Badajoz 169, Mayorazgo IV Etapa, Ate Vitarte, Lima (Peru); Martínez, Lurdes M.; Buleje, Yovanny J. [Centro de Investigación del Estudio de la Actividad Solar y sus Efectos Sobre la Tierra, Facultad de Ciencias, Universidad Nacional San Luis Gonzaga de Ica, Av. Los Maestros S/N, Ica (Peru); Morita, Satoshi [National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo, 181-8588 (Japan); Asai, Ayumi [Unit of Synergetic Studies for Space, Kyoto University, Sakyo, Kyoto, 606-8502 (Japan); UeNo, Satoru; Ishii, Takako T.; Kitai, Reizaburo; Takasao, Shinsuke; Yoshinaga, Yusuke; Otsuji, Kenichi; Shibata, Kazunari, E-mail: denis@kwasan.kyoto-u.ac.jp [Kwasan and Hida Observatories, Kyoto University, Yamashina, Kyoto, 607-8471 (Japan)

    2017-02-10

    Coronal disturbances associated with solar flares, such as H α Moreton waves, X-ray waves, and extreme ultraviolet (EUV) coronal waves, are discussed herein in relation to magnetohydrodynamic fast-mode waves or shocks in the corona. To understand the mechanism of coronal disturbances, full-disk solar observations with high spatial and temporal resolution over multiple wavelengths are of crucial importance. We observed a filament eruption, whose shape is like a “dandelion,” associated with the M1.6 flare that occurred on 2011 February 16 in H α images taken by the Flare Monitoring Telescope at Ica University, Peru. We derive the three-dimensional velocity field of the erupting filament. We also identify winking filaments that are located far from the flare site in the H α images, whereas no Moreton wave is observed. By comparing the temporal evolution of the winking filaments with those of the coronal wave seen in the EUV images data taken by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory and by the Extreme Ultraviolet Imager on board the Solar Terrestrial Relations Observatory-Ahead , we confirm that the winking filaments were activated by the EUV coronal wave.

  10. Radio and white-light observations of coronal transients

    Science.gov (United States)

    Dulk, G. A.

    1980-01-01

    Optical, radio and X-ray evidence of violent mass motions in the corona has existed for some years but only recently have the form, nature, frequency and implication of the transients become obvious. In this paper the observed properties of coronal transients are reviewed, with concentration on the white-light and radio manifestations. The classification according to speeds seems to be meaningful, with the slow transients having thermal emissions at radio wavelengths and the fast ones nonthermal. The possible mechanisms involved in the radio bursts are then discussed and estimates of various forms of energy are reviewed. It appears that the magnetic energy transported from the sun by the transient exceeds that of any other form, and that magnetic forces dominate in the dynamics of the motions. The conversion of magnetic energy into mechanical energy, by expansion of the field, provides a possible driving force for the coronal and interplanetary shock waves.

  11. Fusion-Related Ionization and Recombination Data for Tungsten Ions in Low to Moderately High Charge States

    Directory of Open Access Journals (Sweden)

    Alfred Müller

    2015-05-01

    Full Text Available Collisional processes and details of atomic structure of heavy many-electron atoms and ions are not yet understood in a fully satisfying manner. Experimental studies are required for guiding new theoretical approaches. In response to fusion-related needs for collisional and spectroscopic data on tungsten atoms in all charge states, a project has been initiated in which electron-impact and photon-induced ionization as well as photorecombination of Wq+ ions are studied. Cross sections and rate coefficients were determined for charge states q ranging from q = 1 to q = 5 for photoionization, for q = 1 up to q = 19 for electron-impact ionization and for q = 18 to q = 21 for electron-ion recombination. An overview, together with a critical assessment of the methods and results is provided.

  12. FLARE-GENERATED TYPE II BURST WITHOUT ASSOCIATED CORONAL MASS EJECTION

    Energy Technology Data Exchange (ETDEWEB)

    Magdalenic, J.; Marque, C.; Zhukov, A. N. [Solar-Terrestrial Center of Excellence, SIDC, Royal Observatory of Belgium, Avenue Circulaire 3, B-1180 Brussels (Belgium); Vrsnak, B. [Hvar Observatory, Faculty of Geodesy, Kaciceva 26, HR-10000 Zagreb (Croatia); Veronig, A., E-mail: Jasmina.Magdalenic@oma.be [IGAM/Kanzelhoehe Observatory, Institut of Physics, Universitaet Graz, Universitaetsplatz 5, A-8010 Graz (Austria)

    2012-02-20

    We present a study of the solar coronal shock wave on 2005 November 14 associated with the GOES M3.9 flare that occurred close to the east limb (S06 Degree-Sign E60 Degree-Sign ). The shock signature, a type II radio burst, had an unusually high starting frequency of about 800 MHz, indicating that the shock was formed at a rather low height. The position of the radio source, the direction of the shock wave propagation, and the coronal electron density were estimated using Nancay Radioheliograph observations and the dynamic spectrum of the Green Bank Solar Radio Burst Spectrometer. The soft X-ray, H{alpha}, and Reuven Ramaty High Energy Solar Spectroscopic Imager observations show that the flare was compact, very impulsive, and of a rather high density and temperature, indicating a strong and impulsive increase of pressure in a small flare loop. The close association of the shock wave initiation with the impulsive energy release suggests that the impulsive increase of the pressure in the flare was the source of the shock wave. This is supported by the fact that, contrary to the majority of events studied previously, no coronal mass ejection was detected in association with the shock wave, although the corresponding flare occurred close to the limb.

  13. Rounding of the hippocampus in Alzheimer's disease. A study by routine coronal magnetic resonance imaging

    International Nuclear Information System (INIS)

    Adachi, Michito; Ohshima, Fumi; Kawanami, Toru; Kawakatsu, Shinobu; Shibata, Akiko

    2007-01-01

    On routine coronal images, we have recognized atrophied hippocampi that appear round in patients with Alzheimer's disease (AD). The purpose of this study was to evaluate rounding of the hippocampus in patients with AD and to elucidate whether this change is a useful radiological marker of atrophy of the hippocampus. We enrolled 14 patients with moderate AD (Mini-Mental State Examination score 16.2±3.3) and 15 patients without dementia or neurological deficits as the control group. For measurement of the hippocampus, we used T2-weighted coronal images parallel to the floor of the fourth ventricle. Two observers measured the dimensions of the long and short axes of the hippocampal body of 28 hippocampi from 14 patients with AD and 30 hippocampi from 15 controls. As a marker of rounding of the hippocampal body, we calculated the ratio of the short axis length to the long axis length (the rounding ratio) of the hippocampus. We observed apparent atrophy of the long axis of the hippocampus in patients with AD. An unpaired t-test indicated significant differences in the long axis length and the rounding ratio between the control and AD groups (P<0.01) in the measurements of both observers. However, there was no significant difference in the short axis length. With a threshold of 0.7 in the rounding ratio, the sensitivity was 85.7% and the specificity was 66.7%. The hippocampus appears round on coronal images in the presence of moderate AD. The rounding ratio of the hippocampus is a useful and facile indicator of hippocampal atrophy. (author)

  14. Usefulness of the dynamic gadolinium-enhanced magnetic resonance imaging with simultaneous acquisition of coronal and sagittal planes for detection of pituitary microadenomas.

    Science.gov (United States)

    Lee, Han Bee; Kim, Sung Tae; Kim, Hyung-Jin; Kim, Keon Ha; Jeon, Pyoung; Byun, Hong Sik; Choi, Jin Wook

    2012-03-01

    Does dynamic gadolinium-enhanced imaging with simultaneous acquisition of coronal and sagittal planes improve diagnostic accuracy of pituitary microadenomas compared with coronal images alone? Fifty-six patients underwent 3-T sella MRI including dynamic simultaneous acquisition of coronal and sagittal planes after gadolinium injection. According to conspicuity, lesions were divided into four scores (0, no; 1, possible; 2, probable; 3, definite delayed enhancing lesion). Additional information on supplementary sagittal images compared with coronal ones was evaluated with a 4-point score (0, no; 1, possible; 2, probable; 3, definite additional information). Accuracy of tumour detection was calculated. Average scores for lesion detection of a combination of two planes, coronal, and sagittal images were 2.59, 2.32, and 2.18. 6/10 lesions negative on coronal images were detected on sagittal ones. Accuracy of a combination of two planes, of coronal and of sagittal images was 92.86%, 82.14% and 75%. Six patients had probable or definite additional information on supplementary sagittal images compared with coronal ones alone (10.71%). Dynamic MRI with combined coronal and sagittal planes was more accurate for detection of pituitary microadenomas than routinely used coronal images. Simultaneous dynamic enhanced acquisition can make study time fast and costs low. We present a new dynamic MRI technique for evaluating pituitary microadenomas • This technique provides simultaneous acquisition of contrast enhanced coronal and sagittal images. • This technique makes the diagnosis more accurate and reduces the examination time. • Such MR imaging only requires one single bolus of contrast agent.

  15. Charge migration and charge transfer in molecular systems

    Directory of Open Access Journals (Sweden)

    Hans Jakob Wörner

    2017-11-01

    Full Text Available The transfer of charge at the molecular level plays a fundamental role in many areas of chemistry, physics, biology and materials science. Today, more than 60 years after the seminal work of R. A. Marcus, charge transfer is still a very active field of research. An important recent impetus comes from the ability to resolve ever faster temporal events, down to the attosecond time scale. Such a high temporal resolution now offers the possibility to unravel the most elementary quantum dynamics of both electrons and nuclei that participate in the complex process of charge transfer. This review covers recent research that addresses the following questions. Can we reconstruct the migration of charge across a molecule on the atomic length and electronic time scales? Can we use strong laser fields to control charge migration? Can we temporally resolve and understand intramolecular charge transfer in dissociative ionization of small molecules, in transition-metal complexes and in conjugated polymers? Can we tailor molecular systems towards specific charge-transfer processes? What are the time scales of the elementary steps of charge transfer in liquids and nanoparticles? Important new insights into each of these topics, obtained from state-of-the-art ultrafast spectroscopy and/or theoretical methods, are summarized in this review.

  16. Characteristics of polar coronal hole jets

    Science.gov (United States)

    Chandrashekhar, K.; Bemporad, A.; Banerjee, D.; Gupta, G. R.; Teriaca, L.

    2014-01-01

    Context. High spatial- and temporal-resolution images of coronal hole regions show a dynamical environment where mass flows and jets are frequently observed. These jets are believed to be important for the coronal heating and the acceleration of the fast solar wind. Aims: We studied the dynamics of two jets seen in a polar coronal hole with a combination of imaging from EIS and XRT onboard Hinode. We observed drift motions related to the evolution and formation of these small-scale jets, which we tried to model as well. Methods: Stack plots were used to find the drift and flow speeds of the jets. A toymodel was developed by assuming that the observed jet is generated by a sequence of single reconnection events where single unresolved blobs of plasma are ejected along open field lines, then expand and fall back along the same path, following a simple ballistic motion. Results: We found observational evidence that supports the idea that polar jets are very likely produced by multiple small-scale reconnections occurring at different times in different locations. These eject plasma blobs that flow up and down with a motion very similar to a simple ballistic motion. The associated drift speed of the first jet is estimated to be ≈27 km s-1. The average outward speed of the first jet is ≈171 km s-1, well below the escape speed, hence if simple ballistic motion is considered, the plasma will not escape the Sun. The second jet was observed in the south polar coronal hole with three XRT filters, namely, C-poly, Al-poly, and Al-mesh filters. Many small-scale (≈3″-5″) fast (≈200-300 km s-1) ejections of plasma were observed on the same day; they propagated outwards. We observed that the stronger jet drifted at all altitudes along the jet with the same drift speed of ≃7 km s-1. We also observed that the bright point associated with the first jet is a part of sigmoid structure. The time of appearance of the sigmoid and that of the ejection of plasma from the bright

  17. An RVB state with fermionic charges and bosonic spins: Mean field theory

    International Nuclear Information System (INIS)

    Flensberg, K.; Hedegard, P.; Brix Pedersen, M.

    1989-01-01

    We consider a representation of the Hubbard model, in which the charge carriers are fermions and the spin carriers are bosons. We show that there exist a mean-field solution with a condensate of spin-singlets and we characterize the low temperature behavior of the quasiparticles. Finally we calculate the tunneling spectrum for a normal metal-RVB state tunnel junction and suggest the tunneling experiment as a probe of the statistics of the RVB quasiparticles. (orig.)

  18. A high gradient superconducting quadrupole for a low charge state ion linac

    International Nuclear Information System (INIS)

    Kim, J.W.; Shepard, K.W.; Nolen, J.A.

    1995-01-01

    A superconducting quadrupole magnet has been designed for use as the focusing element in a low charge state linac proposed at Argonne. The expected field gradient is 350 T/m at an operating current of 53 A, and the bore diameter is 3 cm. The use of rare earth material holmium for pole tips provides about 10% more gradient then iron pole tips. The design and the status of construction of a prototype singlet magnet is described

  19. Cyclical Variation of the Quiet Corona and Coronal Holes

    Indian Academy of Sciences (India)

    tribpo

    Key words. Coronagraphs—solar activity cycle—solar corona—total ... can be divided into the quiet sun (including coronal holes) and active regions. The ... regions has attracted attention and is termed as 'the extended solar cycle'. Here the.

  20. Impulsively Generated Wave Trains in Coronal Structures. II. Effects of Transverse Structuring on Sausage Waves in Pressurelesss Slabs

    Science.gov (United States)

    Li, Bo; Guo, Ming-Zhe; Yu, Hui; Chen, Shao-Xia

    2018-03-01

    Impulsively generated sausage wave trains in coronal structures are important for interpreting a substantial number of observations of quasi-periodic signals with quasi-periods of order seconds. We have previously shown that the Morlet spectra of these wave trains in coronal tubes depend crucially on the dispersive properties of trapped sausage waves, the existence of cutoff axial wavenumbers, and the monotonicity of the dependence of the axial group speed on the axial wavenumber in particular. This study examines the difference a slab geometry may introduce, for which purpose we conduct a comprehensive eigenmode analysis, both analytically and numerically, on trapped sausage modes in coronal slabs with a considerable number of density profiles. For the profile descriptions examined, coronal slabs can trap sausage waves with longer axial wavelengths, and the group speed approaches the internal Alfvén speed more rapidly at large wavenumbers in the cylindrical case. However, common to both geometries, cutoff wavenumbers exist only when the density profile falls sufficiently rapidly at distances far from coronal structures. Likewise, the monotonicity of the group speed curves depends critically on the profile steepness right at the structure axis. Furthermore, the Morlet spectra of the wave trains are shaped by the group speed curves for coronal slabs and tubes alike. Consequently, we conclude that these spectra have the potential for inferring the subresolution density structuring inside coronal structures, although their detection requires an instrumental cadence of better than ∼1 s.