3D PiC code investigations of Auroral Kilometric Radiation mechanisms

15th International Congress on Plasma Physics; 13th Latin American Workshop on Plasma Physics

Gillespie, K.M.^1 ; McConville, S.L.^1 ; Speirs, D.C.^1 ; Ronald, K.^1 ; Phelps, A.D.R.^1 ; Bingham, R.^1,2 ; Cross, A.W.^1 ; Robertson, C.W.^1 ; Whyte, C.G.^1 ; He, W.^1 ; Vorgul, I.^3 ; Cairns, R.A.^3 ; Kellett, B.J.^2

SUPA Department of Physics, John Anderson Building, University of Strathclyde, 107 Rottenrow, G4 0NG Glasgow, United Kingdom^1

Space Science and Technology Department, STFC Rutherford Appleton Laboratory, OX11 0QX Didcot, United Kingdom^2

School of Mathematics and Statistics, University of St Andrews, St Andrews, KY16 9SS, United Kingdom^3

关键词: Auroral kilometric radiations;    Cyclotron emission;    Electron cyclotrons;    Geophysical observations;    Horseshoe distribution;    Magnetic dipole;    Maximum Efficiency;    Scaled laboratories;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/511/1/012051/pdf
DOI  :  10.1088/1742-6596/511/1/012051

来源: IOP

【 摘 要 】

Efficient (∼1%) electron cyclotron radio emissions are known to originate in the X mode from regions of locally depleted plasma in the Earths polar magnetosphere. These emissions are commonly referred to as the Auroral Kilometric Radiation (AKR). AKR occurs naturally in these polar regions where electrons are accelerated by electric fields into the increasing planetary magnetic dipole. Here conservation of the magnetic moment converts axial to rotational momentum forming a horseshoe distribution in velocity phase space. This distribution is unstable to cyclotron emission with radiation emitted in the X-mode. Initial studies were conducted in the form of 2D PiC code simulations [1] and a scaled laboratory experiment that was constructed to reproduce the mechanism of AKR. As studies progressed, 3D PiC code simulations were conducted to enable complete investigation of the complex interaction dimensions. A maximum efficiency of 1.25% is predicted from these simulations in the same mode and frequency as measured in the experiment. This is also consistent with geophysical observations and the predictions of theory.