NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Combined Modeling of Acceleration, Transport, and Hydrodynamic Response in Solar FlaresAcceleration and transport of high-energy particles and fluid dynamics of atmospheric plasma are interrelated aspects of solar flares, but for convenience and simplicity they were artificially separated in the past. We present here self consistently combined Fokker-Planck modeling of particles and hydrodynamic simulation of flare plasma. Energetic electrons are modeled with the Stanford unified code of acceleration, transport, and radiation, while plasma is modeled with the Naval Research Laboratory flux tube code. We calculated the collisional heating rate directly from the particle transport code, which is more accurate than those in previous studies based on approximate analytical solutions. We repeated the simulation of Mariska et al. with an injection of power law, downward-beamed electrons using the new heating rate. For this case, a -10% difference was found from their old result. We also used a more realistic spectrum of injected electrons provided by the stochastic acceleration model, which has a smooth transition from a quasi-thermal background at low energies to a non thermal tail at high energies. The inclusion of low-energy electrons results in relatively more heating in the corona (versus chromosphere) and thus a larger downward heat conduction flux. The interplay of electron heating, conduction, and radiative loss leads to stronger chromospheric evaporation than obtained in previous studies, which had a deficit in low-energy electrons due to an arbitrarily assumed low-energy cutoff. The energy and spatial distributions of energetic electrons and bremsstrahlung photons bear signatures of the changing density distribution caused by chromospheric evaporation. In particular, the density jump at the evaporation front gives rise to enhanced emission, which, in principle, can be imaged by X-ray telescopes. This model can be applied to investigate a variety of high-energy processes in solar, space, and astrophysical plasmas.
Document ID
20100017245
Acquisition Source
Marshall Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Liu, Wei
(Stanford-Lockheed Inst. for Space Research Stanford, CA, United States)
Petrosian, Vahe
(Stanford-Lockheed Inst. for Space Research Stanford, CA, United States)
Mariska, John T.
(Naval Research Lab. Washington, DC, United States)
Date Acquired
August 24, 2013
Publication Date
September 10, 2009
Publication Information
Publication: The Astrophysical Journal
Publisher: American Astronomical Society
Volume: 702
Subject Category
Solar Physics
Report/Patent Number
AD-A513382
Funding Number(s)
CONTRACT_GRANT: NAG5 12111
CONTRACT_GRANT: NNM09AA01C
CONTRACT_GRANT: NAG5 11918-1
CONTRACT_GRANT: NSF ATM 0312344
Distribution Limits
Public
Copyright
Other
Keywords
STOCHASTIC ACCELERATION MODEL
ACCELERATION OF PARTICLES
ATMOSPHERIC PLASMA

Available Downloads

There are no available downloads for this record.
No Preview Available