PIC simulations of wave-particle interactions with an initial electron velocity distribution from a kinetic ring current model

Journal Article · Sat Jul 15 00:00:00 EDT 2017 · Journal of Atmospheric and Solar-Terrestrial Physics

DOI:https://doi.org/10.1016/j.jastp.2017.07.004· OSTI ID:1392808

Yu, Yiqun ^[1]; Delzanno, Gian Luca  ^[2]; Jordanova, Vania Koleva  ^[2]; Peng, Ivy Bo ^[3]; Markidis, Stefano ^[3]

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1. Beihang Univ., Beijing (China). School of Space and Environment
2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
3. KTH Royal Inst. of Technology, Stockholm (Sweden)

Whistler wave-particle interactions play an important role in the Earth inner magnetospheric dynamics and have been the subject of numerous investigations. By running a global kinetic ring current model (RAM-SCB) in a storm event occurred on Oct 23–24 2002, we obtain the ring current electron distribution at a selected location at MLT of 9 and L of 6 where the electron distribution is composed of a warm population in the form of a partial ring in the velocity space (with energy around 15 keV) in addition to a cool population with a Maxwellian-like distribution. The warm population is likely from the injected plasma sheet electrons during substorm injections that supply fresh source to the inner magnetosphere. These electron distributions are then used as input in an implicit particle-in-cell code (iPIC3D) to study whistler-wave generation and the subsequent wave-particle interactions. Here, we find that whistler waves are excited and propagate in the quasi-parallel direction along the background magnetic field. Several different wave modes are instantaneously generated with different growth rates and frequencies. The wave mode at the maximum growth rate has a frequency around 0.62ω_ce, which corresponds to a parallel resonant energy of 2.5 keV. Linear theory analysis of wave growth is in excellent agreement with the simulation results. These waves grow initially due to the injected warm electrons and are later damped due to cyclotron absorption by electrons whose energy is close to the resonant energy and can effectively attenuate waves. The warm electron population overall experiences net energy loss and anisotropy drop while moving along the diffusion surfaces towards regions of lower phase space density, while the cool electron population undergoes heating when the waves grow, suggesting the cross-population interactions.

• Research Organization: Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE Laboratory Directed Research and Development (LDRD) Program
• Grant/Contract Number: AC52-06NA25396; 41574156; D621-2013-4309
• OSTI ID: 1392808
• Report Number(s): LA-UR-17-22219
• Journal Information: Journal of Atmospheric and Solar-Terrestrial Physics, Vol. 177; ISSN 1364-6826
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
Heliospheric and Magnetospheric Physics
Wave-particle interactions
Realistic non-Maxwellian electron distribution
Whistler wave generation