List of contributions

Wk. Group 1  Wk. Group 2  Wk. Group 3  Wk. Group 4  Wk. Group 5 

• Presenter: Wojtek Hajdas
  Affiliation: Paul Scherrer Institut
  Authors: W.Hajdas, C.Wigger
  Title:
  RHESSI response modification with the Earth atmosphere and implications for the hard X-ray polarimetry
  Abstract:
  our results will be presented for discussion during the polarimetry splinter group meetings
   

Working group 1

• Presenter: Markus ASCHWANDEN
  Affiliation: Lockheed Martin
  Authors: Markus J. Aschwanden
  Title:
  Particle Propagation in RHESSI Flares
  Abstract:
  Using the energy-dependent time delay measurements in RHESSI data we derive information on particle propagation and trapping in RHESSI flares.
   
• Presenter: Henry Aurass
  Affiliation: Astrophysikalisches Institut Potsdam
  Authors: H. Aurass
  Title:
  The 3D field configuration in a postflare loop system under the termination shock in the main flare phase
  Abstract:
  Possible contributions: - the 3 D magnetic field evolution in a post flare loop system for a flare in which a radio signature of a reconnection outflow termination shock was observed (by combining radio and SOHO MDI data). Relevance for the two-ribbon-flare model, and electron acceleration in the main flare phase. (data from the time before RHESSI was available). - observational facts about radio-visible termination shock effects, and relation with flare ejecta. This is related with Gottfried Mann's talk.
   
• Presenter: Marina Battaglia
  Affiliation: Institut of Astronomy, ETH Zurich
  Authors: Marina Battaglia, Paolo C. Grigis, Arnold Benz
  Title:
  Size dependence of solar X-ray flare properties
  Abstract:
  Non-thermal and thermal parameters of 86 flares of GOES class B1 to M9 (background subtracted classes A1 to M9) have been compared to each other. The hard X-ray flux has been measured by RHESSI and a spectral fitting provided flux and spectral index of the non-thermal emission, as well as temperature and emission measure of the thermal emission. The soft X-ray flux was taken from GOES measurements. We find a linear correlation in a double logarithmic plot between the non-thermal flux and the spectral index. The relation is similar to the one found by a comparison of the same parameters from several sub-peaks of one single flare. Thus small flares are like small subpeaks of large flares. Thermal flare properties such as temperature, emission measure and the soft X-ray flux also correlate with peak non-thermal flux. A large non-thermal peak flux entails an enhancement in all thermal parameters. The relation between spectral index and the non-thermal flux is an intrinsic feature of the particle acceleration process, depending on flare size. This property affects the reported frequency distribution of flare energies.
   
• Presenter: Paolo Grigis
  Affiliation: ETH Zurich
  Authors: Paolo Grigis & Arnold Benz
  Title:
  Evolution of reconnection along an arcade of magnetic loops
  Abstract:
  RHESSI observations of a solar flare showing continuous motions of double hard X-ray sources interpreted as footpoints of magnetic loops are presented. The temporal evolution shows many distinct emission peaks of duration of some tens of seconds ('elementary flare bursts'). Elementary flare bursts have been interpreted as instabilities or oscillations of the reconnection process leading to an unsteady release of magnetic energy. These interpretations based on two-dimensional concepts cannot explain these observations, showing that the flare elements are displaced in a third dimension along the arcade. Therefore, the observed flare elements are not a modulation of the reconnection process, but originate as this process progresses along an arcade of magnetic loops. Contrary to previous reports, we find no correlation between footpoint motion and hard X-ray flux. This flare apparently contradicts the predictions of the standard translation invariant 2.5D reconnection models.
   
• Presenter: Gordon Holman
  Affiliation: NASA's Goddard Space Flight Center
  Authors:
  Title:
  
  Abstract:
  Group Leader
   
• Presenter: Jana Kasparova
  Affiliation: Astronomical Institute
  Authors: Jana Kasparova, Eduard Kontar
  Title:
  Searching for RHESSI spectra affected by albedo
  Abstract:
  The contribution will present the first results from automatic search procedure for photon spectra affected by albedo.
   
• Presenter: Eduard Kontar
  Affiliation: University of Glasgow
  Authors:
  Title:
  
  Abstract:
  I'm interested in: - albedo and directivity of HXR emission - model independent inversion of photon spectra - wave-particle interactions
   
• Presenter: Gottfried Mann
  Affiliation: Astrophysikalisches Institut Potsdam
  Authors: G. Mann, H. Aurass, and A. Warmuth
  Title:
  Electron Acceleration at the Reconnection Outflow Shock During Solar Flares
  Abstract:
  In the solar corona magnetic field energy is suddenly released by magnetic reconnection during flares. Hot jets appear in the outflow region of the reconnection site. If these jets penetrate into the surrounding plasma, standing shocks are established. There, electrons can be accelerated by shock drift acceleration up to high energies. This mechanism is treated in a fully relativistic manner. If the energetic electrons travel along the magnetic field lines towards the denser chromosphere, they can emit hard X-ray radiation via bremsstrahlung. The theoretically obtained results are compared with radio and hard X-ray data of the solar event on October 28, 2003, at which signatures of highly relativistic electrons has been observed.
   
• Presenter: Anna Maria Massone
  Affiliation: LAMIA - INFM, Genova
  Authors: A. M. Massone, M. Piana, J. C. Brown, A.
  Title:
  A software package for the reconstruction of averaged electron spectra
  Abstract:
  We describe an IDL software for the inversion of photon RHESSI spectra based on the regularization theory for solving ill-conditioned inverse problems. The method provides the averaged electron spectra with estimate of the error propagation on the solution
   
• Presenter: Mark McConnell
  Affiliation: University of New Hampshire
  Authors: M.L. McConnell, D. M. Smith, A.G. Emslie
  Title:
  Update on Solar Flare Polarimetry with Rhessi
  Abstract:
  Will provide the latest results on our efforts to study hard X-ray solar flare polarization with RHESSI.
   
• Presenter: Michele Piana
  Affiliation: Dipartimento di Matematica Universita di Genova
  Authors: M. Piana, M. Prato, J. C. Brown, A. M. M
  Title:
  An inversion method for the thermal bremsstrahlung problem
  Abstract:
  A numerical method for reconstructing the differential emission measure from thermally interpreted bremsstrahlung photon spectra is introduced. The method is based on the Tikhonov regularization theory for solving ill-conditioned inverse problems. Application
   
• Presenter: Linhui Sui
  Affiliation: CUA /GSFC
  Authors: Sui, L., Holman, G. D., Dennis, B. R.
  Title:
  The Low-Energy Cutoff to the Nonthermal Electron Spectrum
  Abstract:
  Since the spectrum of electrons accelerated during a solar flare is a steeply falling function, most of the energy in these electrons resides with the lower energy particles. Thus, it is most important to determine the low energy end of the spectrum, part...
   
• Presenter: Mikko Väänänen
  Affiliation: Observatory, University of Helsinki
  Authors: Mikko Väänänen, Juhani Huovelin, Lauri Alha
  Title:
  XSM, GOES and RHESSI flux cross-calibrations / Recent RHESSI work
  Abstract:
  I will present the calibration results of the XSM and GOES in the 1.55-12.40keV band and XSM and RHESSI in the 5-8kev band. The calibration results provide insight into the scientific fidelity of the instruments and their data. In addition recent RHESSI work on a statistical flare survey is covered.
   

Working group 2

• Presenter: Weiqun Gan
  Affiliation: Purple Mountain Observatory
  Authors: Gan, W.Q. et al.
  Title:
  1) Gamma-ray aspect of X7.1 flare on Jan.20
  2) I-J Interactions in Gamma-ray Line Flares
  Abstract:
  Abstract 1
  The general senario of the flare are described based mainly on the data from RHESSI, SXI/GOES, and TRACE. A 2.2 MeV image is shown in comparsion with the hard X-ray images. The gamma-ray spectrum for the whole time integration as well as for several time intervals are fitted. The deduced line fluence are compared among the other gamma-ray line flares.
  Abstract 2
  We estimate the production of gamma-radiation in the processes of interactions of energetic (accelerated) heavy and middle nuclei with that of elements of the solar atmosphere (so-called i-j interactions). We compare our theoretical estimates with RHESSI observations for the flare of 2002 July 23. It was shown that the $^{24}$Mg gamma-ray emission in this event was produced by the new generated Mg nuclei. With a high probability, the gamma-ray line emission of $^{28}$Si nuclei from this flare was caused by the same processes.
  (Note: Another contribution in working group 3)
   
• Presenter: Alexander MacKinnon
  Affiliation: University of Glasgow
  Authors: A MacKinnon, M Toner
  Title:
  Alpha-particle and proton distributions
  Abstract:
  We apply the procedure of Toner and MacKinnon (2004, SP 223 159) to published RHESSI gamma-ray line fluences from the 23 July 2002 flare. Allowed ranges of proton and alpha-particle energy distribution parameters are delineated without assuming these are ...
   
• Presenter: Michael R. Moser
  Affiliation: Physikalisches Institut, University of Bern
  Authors: M.R. Moser, E.O. Flückiger, J.M. Ryan, M.L. McConnell, R.S. Miller
  Title:
  Direct observation of solar flare neutrons
  Abstract:
  Neutrons produced in solar flares by nuclear proton and ion interactions over a wide range of energies provide important information on the 50-300 and <10 MeV regimes, complementing gamma-ray observations. Due to the long neutron capture times on He-3 and H (~100s) and the fact that neutrons are produced over a wide energy range, the 2.223 MeV neutron-capture gamma-ray line has limited utility for measuring the proton and ion spectra between 40 and 300 MeV. The spectrum of accelerated and interacting ions can be deduced more reliably from direct neutron measurements. I will give a short introduction on the topic and will then concentrate on the recent development of next generation space borne solar neutron detectors.
   
• Presenter: Gerald Share
  Affiliation: Naval Research Laboratory
  Authors: Gerald Share/Ronald Murphy
  Title:
  Annihilation and Nuclear Lines in Flares
  Abstract:
  I will report on the annihilation and nuclear line analyses of RHESSI flares, including those observed in January 2005.
   
• Presenter: Gerard Trottet
  Affiliation: Observatoire de Paris-Meudon, LESIA
  Authors: Gerard Trottet
  Title:
  Possible radio diagnostics of flare accelerated positrons
  Abstract:
  Radio observations at frequencies above 200 GHz of two large solar flares have revealed spectra which increase with frequency. We discuss possible interpretations of this new spectral component and argue that synchrotron emission from high energy positron...
   
• Presenter: Valentina Zharkova
  Affiliation: Bradford University
  Authors: V.Zharkova, M.Godrovskyy, Y.M. Voitenko and M.Goossens
  Title:
  Proton and electron acceleration by electric field in a 3D RCS and its effect on flare diagnostics
  Abstract:
  We shall discuss the consequences on flare diagnostics of the ejection of fully or partially separated electron-proton beams for a few magnetic field topologies.
   

Working group 3

• Presenter: Laura Bone
  Affiliation: University of Glasgow
  Authors: Laura Bone, John Brown, Lyndsay Fletcher
  Title:
  Multiwavelength observations of a partially occulted solar flare.
  Abstract:
  On 20th July 2002 an X3.3 flare occurred in active region 0039, then behind the Suns east limb. The occultation height was estimated to be 11000km. The flare was observed simultaneously by the RHESSI satellite and the Solar X-ray/Cosmic Gamma Ray Burst experiment on Ulysses, then located behind the limb. From these observations we can infer that the coronal component of the hard x-ray flux is a significant fraction of the total hard X-ray flux between 25-150KeV. High column densities (>10e20cm^3) were also obtained. We present a possible mechanism for obtaining anomalous density in the corona, within the context of a coronal thick target model.
   
• Presenter: Frantisek Farnik
  Affiliation: Astronomical Institute, Academy of Sciences
  Authors: Frantisek Farnik and Marian Karlicky
  Title:
  Hard X-ray emission and its relation to reverse drift bursts in the 0.8 - 4.5 GHz range
  Abstract:
  Nine examples of the reverse drift bursts (RDB) observed in the 0.8-4.5 GHz frequency range by the Ondrejov radiospectrograph and associated with hard X-ray emissions (RHESSI) are studied in detail. Most of them were observed at the beginning of flares or during the rise phase. The frequency drift of the reverse drift bursts and the time delays of the associated X-ray peaks are found to be 20-2500 MHz/s and 1-3.5 s, respectively. Fast changes of positions or shape of the hard X-ray sources are recognized in many of the studied events. It indicates a propagation of electron beams along magnetic field lines with diverging magnetic field connectivities. Finally, relatively low frequency drifts of the observed RDB are discussed.
   
• Presenter: Weiqun Gan
  Affiliation: Purple Mountain Observatory
  Authors: Gan, W.Q. et al.
  Title:
  Shrinkage of Flare Radio Loops
  Abstract:
  We present a direct example of the shrinkage of flare loops from the radio observation of a limb X3.1 flare occurring at 00:49 UT on August 24, 2002. The relation between the positions of X-ray and radio images is shown. In the rising phase of 9 minutes the loop in the radio image at 34 GHz shrank by about 30\%, suggesting a downward speed of approximately 13 km\,s$^{-1}$. In about 2 minutes after the peak of the intense energy injection the shrinkage of the radio loop was evolved into expansion.
  Note: other contributions in working group 2!
   
• Presenter: Guangli Huang
  Affiliation: Purple Mountain Observatory
  Authors: Huang Guangli & Ji Haisheng
  Title:
  Descrepancy of microwave and hard X-ray sources in two selected events
  Abstract:
  Solar microwave and hard X-ray bursts are resulted from the same populations of non-thermal electrons accelerated from the reconnection sites. However, some discrepancies of microwave and hard X-ray spectra and time profiles have been discussed in a serie ...
   
• Presenter: Karl-Ludwig Klein
  Affiliation: Observatoire de Paris
  Authors: K.-L. Klein, S. Krucker
  Title:
  
  Abstract:
  We present radio, X-ray and context observations during a flare on 24 April 2003. The event comprises unusually well observed type II and type IV bursts with a rich set of context observations that allow us to address questions on - the propagation of the type II shock as related to a CME and the moving type IV source, - the relationship of HXR and different types of radio emission, - the delayed release of solar energetic electrons as compared to the acceleration od interacting electrons.
   
• Presenter: MUKUL KUNDU
  Affiliation: UNIV of Maryland
  Authors: M R KUNDU,E J Schmahl,V I Garaimov,S M W
  Title:
  RHESSI & NoRH Observations of some Large Solar Flares
  Abstract:
  Simultaneous Imaging Observations by RHESSI and Nobeyama Radio Heliograph of some large flares:November 3,2003, June17,2003, Oct26,2003.
   
• Presenter: Adriana V. R. Silva
  Affiliation: CRAAM/Mackenzie University
  Authors: Adriana V. R. Silva, C. G. Gimenez de Castro, P. Kaufmann
  Title:
  Comparative analysis of the submm emission from the 02-Nov-2003 flare
  Abstract:
  The flare on November 2nd, 2003, at 17:06 UT, occurred on the very active region 486 located at S14W56 on this day. This flare was classified as a X8.3 and 2B event. This flare is one of the few events detected simultaneously by RHESSI and the Solar Submillimeter Telescope (SST) at 212 and 405 GHz. The emission at these high frequencies is produced by larger than 1 MeV electrons. The goal is to study the hard X-rays from this population of electrons and compare the parameters obtained for the acceleraded electron distribution from both wavelength regimes.
   

Working group 4

• Presenter: Steven Christe
  Affiliation: Space Science Laboratory
  Authors: Space Science Laboratory
  Title:
  Microflare Statistics and Frequency Distribution
  Abstract:
  RHESSI is uniquely suited to observe solar microflares due to its unique sensitivity in the 3-15 keV energy range (up to $\sim$100 times better than previous solar instruments). As such, it provides new information on these low level transients. Initial results (Krucker et al 2002, Benz & Grigis 2002) suggest that microflares are different from larger flares. They are more often associated with steep nonthermal spectra (power law index -5 to -7). In this study, we present microflare statistics from times of low activity. A list of microflares was created by applying the standard RHESSI flare-finding algorithm to the lower 6-12 keV energy range ($\sim$10 000 events). Imaging was used in order to obtain positions of solar events and reject non-solar events. These solar events were then each spectrally analyzed. We present microflare statistics, including active region productivity, and the microflare frequency distribution. This work was supported by NASA contract NAS5-98033.
   
• Presenter: Brian Dennis
  Affiliation: NASA Goddard Space Flight Center
  Authors: Dennis, B. R. and Phillips, K. J. H.
  Title:
  Separation of Thermal and Nonthermal Emissions
  Abstract:
  I will present the latest understanding on the analysis of RHESSI spectral data below 10 keV using Chianti version 5. I will show how the Fe and Fe/Ni line complexes at ~6.7 and 8.2 keV, respectively, can help to separate the thermal and nonthermal components
   
• Presenter: Lyndsay Fletcher
  Affiliation: University of Glasgow
  Authors: L. Fletcher, D. A. Brown, H. S. Hudson
  Title:
  UV ribbons and Hard X-ray footpoints
  Abstract:
  We address the issue of the location of hard X-ray footpoints in flares. Why do flares typically only show two or three footpoints at specific locations in flare ribbons? What (perhaps in the magnetic field configuration) determines their location, and do...
   
• Presenter: Peter Gallagher
  Affiliation: University College Dublin
  Authors: Gallagher, P. T., Milligan, R., Schwartz, R.
  Title:
  Chromospheric and Transition Region Response
  Abstract:
  Simultaneous observations of chromospheric evaporation are presented using RHESSI and CDS. RHESSI X-ray images and spectra were used to determine the flux of non-thermal electrons accelerated during the impulsive phase of an M2.2 flare. Assuming a thick-target model, the injected electron spectrum was found to have a spectral index of ∼7.3, a low energy cut-off of ∼21 keV, and a resulting flux of ∼2×10^10 ergs cm−2 s−1. The dynamic response of the atmosphere was determined using CDS spectra, which indicate upflow velocities of 260±15 km s −1 in Fe XIX (592.23 A), and associated downflows of ≤30 km s−1 at chromospheric and transition region temperatures. The properties of the accelerated electron spectrum and the corresponding evaporative velocities were found to be entirely consistent with gentle rather than explosive evaporation.
   
• Presenter: Jean-Claude HENOUX
  Affiliation: Observatoire de Paris, LESIA
  Authors: Jean-Claude Hénoux, Gilbert Chambe, Zhi
  Title:
  flare Impact polarization observed with THEMIS
  Abstract:
  Linear polarization has been observed in the Halpha and Hbeta lines in a solar flare observed with THEMIS. This polarization is located at the border of a flare kernel and in a surge with directions of polarization respectively radial and tangential. At the border of the flare kernel the polarization is interpreted as due to beam bombrdment, and in the surge to the electric current at the origin of the electromagnetic force that lift the matter.
   
• Presenter: Hugh Hudson
  Affiliation: Space Sciences Lab, UC Berkeley
  Authors: H. Hudson, L. Fletcher
  Title:
  Implications of compact footpoints
  Abstract:
  RHESSI hard X-ray imaging frequently does not resolve the footpoints of flare loops. This is consistent with observations in closely-related emissions (UV and white light), which often do not resolve the footpoints with TRACE resolution (0.5 arc s pixels). We discuss the implications of these results from the point of view of energy transport in the impulsive phase.
   
• Presenter: Haisheng Ji
  Affiliation: Purple Mountain Observatory
  Authors: Haisheng Ji, Haimin Wang
  Title:
  Converging motion of solar flare kernels
  Abstract:
  We present a number of examples of solar flares, in which conjugate kernels move toward each other during the impulsive phase. The normal separation motion occurs only after impulsive phases. Meanwhile, the height of coronal HXR sources follow a U-shaped time profile, decreasing first and then increasing after the impulsive phase. We can infer reconnection behavior by analyzing these motion patterns. A detailed investigation to the reconnection behavior of an M-class flare is given.
   
• Presenter: Sam Krucker
  Affiliation: SSL, UC Berkeley
  Authors: Krucker, Balciunaite, Christe, Lin
  Title:
  Coronal HXR sources in partly occulted flares
  Abstract:
  
   
• Presenter: James McTiernan
  Affiliation: Space Sciences Lab, University of California
  Authors: J. McTiernan
  Title:
  Multi-Instrument Diffferent Emission Measure Calculations
  Abstract:
  I will summarize calculations of the DEM for active regions and flares using RHESSI and other instruments, the calculations include, RHESSI, GOES, GOES-SXI, and will soon include EIT and TRACE. The DEM calculations use the pixon reconstruction technique
   
• Presenter: Monique Pick
  Affiliation: Observatoire de Paris
  Authors: G. Mason, M. Pick, S. Krucker, Y.M. Wang
  Title:
  Origin and propagation of impulsive heavy -ion rich energetic events;
  Abstract:
  Using multi-instrumental sources of data, we present preliminary results on the origin and propagation of impulsive He3 and heavy-ion rich energetic events. The association with CMEs is investigated. We concentrate on events taking place during the observation time of the Naçay Radioheliograph and also observed by RHESSI.
   
• Presenter: Edward Schmahl
  Affiliation: University of Maryland & NASA/GSFC Lab for Solar & Space Physics
  Authors: E.J. Schmahl
  Title:
  Hard & soft X-ray and EUV pre-flare phenomena
  Abstract:
  
   
• Presenter: Manuela Temmer
  Affiliation: IGAM/Institute of Physics, UNI Graz
  Authors: Temmer M., Veronig A., Vrsnak B., Miklenic C.
  Title:
  Hard X-ray emission and flare ribbon expansion in the X3.8 flare of 17-Jan-2005
  Abstract:
  For the X3.8 flare of 17 January 2005 we study hard X-ray footpoint motions observed by RHESSI and flare ribbon motions as seen in H-alpha images from Kanzelhöhe Observatory. Using photospheric magnetic field measurements from SoHO/MDI we investigate magnetic reconnection rates and the temporal relation of hard X-ray emission and flare ribbon expansion.
   
• Presenter: Astrid Veronig
  Affiliation: Institute of Physics, University of Graz
  Authors: A.M. Veronig, M. Karlicky, B. Vrsnak, M. Temmer, B.R. Dennis, J. Magdalenic, W. Otruba, W. Poetzi
  Title:
  X-ray loop-top altitude decrease in an X Loop-top altitude decrease in an X-class flare
  Abstract:
  We studied RHESSI X-ray source motions in the 2003 November 3, X3.9 flare together with complementary data from SXI, EIT, and Kanzelh\"ohe H$\alpha$. Particular emphasis was laid on the apparent altitude decrease of the RHESSI X-ray loop-top (LT) source early in the flare before changing to the commonly observed upward growth of the flare loop system. Our main observational results agree with recent findings from Sui and Holman (2003) and Sui et al. (2004) in that at higher photon energies the LT source is located at higher altitudes and shows higher downward velocities than at lower energies. For this flare, the LT altitude decrease was also observed by the SXI instrument. RHESSI spectra indicate that during the time of LT altitude decrease the emission of the LT source is thermal bremsstrahlung from a "superhot" plasma with temperatures up to 45 MK. Finally, we show simulation results from a magnetic collapsing trap model which can reproduce the key observational findings in case that the emission in the LT is thermal bremsstrahlung.
   

Working group 5

• Presenter: Kaspar Arzner
  Affiliation: Paul Scherrer Institut
  Authors: Kaspar Arzner, Loukas Vlahos
  Title:
  Acceleration in a force-free corona with anomaleous resistivity
  Abstract:
  We simulate exact and gyrokinetic electron orbits in linear force-free coronal magnetic fields extrapolated from SOHO/MDI magentograms with anomaleous resistivy. The latter is localized in regions where the magnetic twist $\nabla \times \bhat$ exceeds a given threshold. While the electron transport between the resistive regions is mostly adiabatic, this is necessarily not true inside the dissipation regions where are accelerated by a parallel electric field ${\bf E} = \eta {\bf j}$. In order to gain observational predictions we inject super-Dreicer particles at $t$ = 0 inside the dissipation regions and follow them up to $t$ = 10s. Precipitating electrons which leave the simulation system at height $z$ =0 are associated with hard X rays, electrons which escape at height $z$ $\sim$ 30.000km are associated with normal-drifting type IIIs. A third, trapped, population is related to synchrotron emission. Time profiles and spectra of all three emissions are calculated, and their dependency on the geometrical model parameters and on anomaleous resistivity is explored. It is found that acceleration predominantly takes place at low latitudes ($\la$ 20.000 km), so that electrons reach the chromosphere ($z$ = 0) quickest and most likely, suggesting that HXR lead the radio waves.
   
• Presenter: Arnold Benz
  Affiliation: ETH Zürich
  Authors: Arnold Benz, Paolo Grigis, Marina Battaglia
  Title:
  Observational Constraints for Stochastic Acceleration
  Abstract:
  Flare observations are critically reviewed concerning evidence for and against stochastic acceleration. Some forms for stochastic acceleration are sensitive to the difference between electron and ions, others are not. The stochastic diffusion equation is discussed for for different electron acceleration scenarios. The goal is to find out what is the physical origin of the diffusion terms.
   
• Presenter: Marco Onofri
  Affiliation: University of Thessaloniki
  Authors: M. Onofri, L. Primavera, F. Malara, P.Veltri
  Title:
  MHD turbulence development in a 3D current sheet
  Abstract:
  
   
• Presenter: Nicole VILMER
  Affiliation: LESIA- Observatoire de Paris
  Authors: N.Vilmer
  Title:
  Constraints on acceleration mecahnisms from relativistic electrons and ions.
  Abstract:
  
   
• Presenter: Loukas Vlahos
  Affiliation: Department of Physics
  Authors: Kaspar Arzner and Loukas Vlahos
  Title:
  Particle acceleration and energy release in complex magnetic topologies
  Abstract:
  We will present simuatios on the acceleration of particles in realistic magnetic topologies.
   

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