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Fermi Observations of Particle acceleration in Solar Flares

发布时间:2018-04-20 15:18来源:未知 责任编辑:于莹

报告题目:Fermi Observations of Particle acceleration in Solar Flares

报 告 人:Professor Vahe Petrosian

报告时间:2018年05月08日 16时00分

报告地点:天文楼212报告厅

报 告 人:Professor Vahe  Petrosian, On behalf of the Fermi collaboration
 
报告时间:2018年05月08日 16时00分
 
报告地点:天文楼212报告厅
 
报告题目:Fermi Observations of Particle acceleration in Solar Flares:
 
报告摘要:
 
During the current solar cycle of the Sun the Fermi Large Area Telescope (LAT)
has detected more than 40 flares up to GeV energies, some lasting many hours
contemporaneous with Solar Energetic Particles (SEPs) and three that originate
from active regions (AR) located behind the limb (BTL) as viewed from the Earth
and detected by STEREO observations. Almost all are associated with fast Coronal
Mass Ejections (CMEs). I will give a brief overview of the observations
with focus on two of the three BTL flares that show RHESSI hard X-ray and SDO
EUV  emission coming from the top of a relatively large flare loop peeking over
the limb. Radio emission with similar light curves is also attributed to this
looptop source, while the centroids of the  LAT gamma-rays are some distances
away. This multiwavelength coverage of the well isolated looptop (presumably
near the coronal acceleration site) combined with Fermi observations provides a
unique opportunity to investigate possible mechanisms and sites of acceleration
of particles (corona and/or CME shock), their transport and radiative signatures
(leptonic or hadronic). I will present some quantitative result on accelerated
particle spectra, magnetic field values at the looptop and its structure
connecting the AR to the CME and back to the LAT source.
 
 报告人简介:
 
Vahe Petrosian, Professor of physics and applied physics, Chairman of Astronomy Program, Department of Physics, Stanford University.

Awards and recognition: 1972-74 Alfred P. Sloan Fellow; Member, Eta Kappa Nu, Tau Beta Pi; Center for Space Science and Astrophysics & KIPAC, Stanford University; Co-discoverer of strong gravitational lensing of cluster of galaxies, Inventor of Petrosian criteria (magnitude, ratio) with non-parametric methods for determination of distribution of astronomical sources from truncated data.
 


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