Particle Motion and Energization in a Chaotic Magnetic Field

Journal Article · Wed Nov 11 00:00:00 EST 2009 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.3266777· OSTI ID:21325592

Li, G; Dasgupta, B; Webb, G ^[1]; Ram, A K ^[2]

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1. CSPAR, University of Alabama in Huntsville, Huntsville, AL 35899 (United States)
2. Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

In nature there are many systems where macroscopic and time varying currents exist. For example, in solar flares, currents in the form of filaments and/or loops have been observed. In a simple asymmetric configuration where steady state currents flow through a straight wire and a loop, a somewhat surprising feature is that the resulting magnetic field can become chaotic depending on the relative size of the currents. This implies that studying particle motion in a time-dependent chaotic magnetic field is a fundamental problem in space plasma physics and it has profound implications to astrophysical phenomena as the solar flares. Because these currents are time dependent, they induce electric fields. Consequently, electrons and ions moving in the field can experience alternating acceleration and deceleration, leading to a second order Fermi acceleration. We discuss here charged particle motion in a chaotic magnetic fields and the energization process. Particle trajectories are obtained by following single particle motion using the Lorentz equation by a 4-th order Runge-Kutta scheme. Implications of our results to particle acceleration and heating at a flare site are discussed.

• OSTI ID: 21325592
• Journal Information: AIP Conference Proceedings, Vol. 1183, Issue 1; Conference: 18. annual international astrophysics conference, Kona, HI (United States), 1-7 May 2009; Other Information: DOI: 10.1063/1.3266777; (c) 2009 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ACCELERATION
ASTROPHYSICS
ASYMMETRY
CHARGED-PARTICLE TRANSPORT
COSMIC RADIATION
ELECTRIC CURRENTS
ELECTRIC FIELDS
ELECTRONS
FOKKER-PLANCK EQUATION
INTERPLANETARY MAGNETIC FIELDS
IONS
PLASMA
RUNGE-KUTTA METHOD
SOLAR FLARES
SPACE
STEADY-STATE CONDITIONS
TIME DEPENDENCE