Particle energization through time-periodic helical magnetic fields
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Mitra-2014-Particle energization through.pdf
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Author(s)
Mitra, Dhrubaditya
Brandenburg, Axel
Dasgupta, Brahmananda
Niklasson, Eyvind
Ram, Abhay
Ram, Abhay K.
Date Issued
April 2014
Journal
Physical Review E
Publisher
American Physical Society
Citation
Mitra, Dhrubaditya, Axel Brandenburg, Brahmananda Dasgupta, Eyvind Niklasson, and Abhay Ram. “Particle Energization through Time-Periodic Helical Magnetic Fields.” Phys. Rev. E 89, no. 4 (April 2014). © 2014 American Physical Society.
Version
Final published version
Abstract
We solve for the motion of charged particles in a helical time-periodic ABC (Arnold-Beltrami-Childress) magnetic field. The magnetic field lines of a stationary ABC field with coefficients A=B=C=1 are chaotic, and we show that the motion of a charged particle in such a field is also chaotic at late times with positive Lyapunov exponent. We further show that in time-periodic ABC fields, the kinetic energy of a charged particle can increase indefinitely with time. At late times the mean kinetic energy grows as a power law in time with an exponent that approaches unity. For an initial distribution of particles, whose kinetic energy is uniformly distributed within some interval, the probability density function of kinetic energy is, at late times, close to a Gaussian but with steeper tails.
MIT Department
Massachusetts Institute of Technology. Plasma Science and Fusion Center
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Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
https://doi.org/10.1103/PhysRevE.89.042919
