Numerical modeling of artificial ionospheric layers driven by high-power HF heating

TY - JOUR

T1 - Numerical modeling of artificial ionospheric layers driven by high-power HF heating

AU - Eliasson, Bengt

AU - Shao, Xi

AU - Milikh, Gennady

AU - Mishin, Evgeny V.

AU - Papadopoulos, Dennis K.

PY - 2012

Y1 - 2012

N2 - We present a multi-scale dynamic model for the creation and propagation of artificial plasma layers in the ionosphere observed during high-power high-frequency (HF) heating experiments at HAARP. Ordinary (O) mode electromagnetic (EM) waves excite parametric instabilities and strong Langmuir turbulence (SLT) near the reflection point. The coupling between high-frequency electromagnetic and Langmuir waves and low-frequency ion acoustic waves is numerically simulated using a generalized Zakharov equation. The acceleration of plasma electrons is described by a Fokker-Planck model with an effective diffusion coefficient constructed using the simulated Langmuir wave spectrum. The propagation of the accelerated electrons through the non-uniform ionosphere is simulated by a kinetic model accounting for elastic and inelastic collisions with neutrals. The resulting ionization of neutral gas increases the plasma density below the acceleration region, so that the pump wave is reflected at a lower altitude. This leads to a new turbulent layer at the lower altitude, resulting in a descending artificial ionized layer (DAIL), that moves from near 230 km to about 150 km. At the terminal altitude, ionization, recombination, and ambipolar diffusion reach equilibrium, so the descent stops. The modeling results reproduce artificial ionospheric layers produced for similar sets of parameters during the high-power HF experiments at HAARP.

AB - We present a multi-scale dynamic model for the creation and propagation of artificial plasma layers in the ionosphere observed during high-power high-frequency (HF) heating experiments at HAARP. Ordinary (O) mode electromagnetic (EM) waves excite parametric instabilities and strong Langmuir turbulence (SLT) near the reflection point. The coupling between high-frequency electromagnetic and Langmuir waves and low-frequency ion acoustic waves is numerically simulated using a generalized Zakharov equation. The acceleration of plasma electrons is described by a Fokker-Planck model with an effective diffusion coefficient constructed using the simulated Langmuir wave spectrum. The propagation of the accelerated electrons through the non-uniform ionosphere is simulated by a kinetic model accounting for elastic and inelastic collisions with neutrals. The resulting ionization of neutral gas increases the plasma density below the acceleration region, so that the pump wave is reflected at a lower altitude. This leads to a new turbulent layer at the lower altitude, resulting in a descending artificial ionized layer (DAIL), that moves from near 230 km to about 150 km. At the terminal altitude, ionization, recombination, and ambipolar diffusion reach equilibrium, so the descent stops. The modeling results reproduce artificial ionospheric layers produced for similar sets of parameters during the high-power HF experiments at HAARP.

KW - artificial ionospheric layers

KW - electron acceleration

KW - Langmuir turbulence

KW - high-frequency heating

UR - http://onlinelibrary.wiley.com/doi/10.1029/2012JA018105/abstract

U2 - 10.1029/2012JA018105

DO - 10.1029/2012JA018105

M3 - Article

VL - 117

JO - Journal of Geophysical Research: Oceans

JF - Journal of Geophysical Research: Oceans

SN - 0148-0227

IS - A10

M1 - A10321

ER -