Estimation of HF artificial ionospheric turbulence characteristics using comparison of calculated plasma wave decay rates with the measured decay rates of the stimulated electromagnetic emission

详细信息    查看全文

• 作者：D.D. Bareev ; V.G. Gavrilenko ; S.M. Grach ; ^{sgrach@rf.unn.ru" class="auth_mail" title="E-mail the corresponding author} ; E.N. Sergeev¹
• 关键词：Ionosphere ; HF pumping ; Stimulated electromagnetic emission ; Plasma waves ; Damping rate
• 刊名：Advances in Space Research
• 出版年：2016
• 出版时间：1 February 2016
• 年：2016
• 卷：57
• 期：3
• 页码：802-812
• 全文大小：1013 K

文摘

It is shown experimentally that the relaxation time of the stimulated electromagnetic emission (SEE) after the pump wave turn off decreases when frequency of the electromagnetic wave, responsible for the SEE generation (pump wave f₀$f_0$ or diagnostic wave f_dw$f_{\mathrm{dw}}$) approaches 4th harmonic of the electron cyclotron frequency f_ce$f_{\mathrm{ce}}$. Since the SEE relaxation is determined by the damping rate of plasma waves with the same frequency, responsible for the SEE generation, we calculated damping rates of plasma waves with ω∼ω_uh$\omega \sim {\omega }_{\text{uh}}$ (ω$\omega$ is the plasma wave frequency, ω_uh${\omega }_{\text{uh}}$ is the upper hybrid frequency) for frequencies close to and distant from the double resonance where ω_uh∼4ω_ce${\omega }_{\text{uh}}\sim 4{\omega }_{\text{ce}}$ (ω_ce=2πf_ce${\omega }_{\text{ce}}=2\pi f_{\mathrm{ce}}$). The calculations were performed numerically on the base of linear plasma wave dispersion relation at arbitrary ratio between |Δ|=ω-4ω_ce$|\mathrm{\Delta }|=\omega -4{\omega }_{\text{ce}}$ and |k_‖|V_Te$|k_{\Vert }|V_{{\text{T}}_{\text{e}}}$ (V_Te$V_{{\text{T}}_{\text{e}}}$ is the electron thermal speed and k_‖$k_{\Vert }$ is the projection of the wave vector onto the magnetic field direction. A comparison of calculation and experimental results has shown that obtained frequency dependence of the SEE decay rate is similar to the damping rate frequency dependence for plasma waves with wave vectors directed at the angles 60–70° to the magnetic field, and gives a strong hint that oblique upper hybrid plasma waves should be responsible for the SEE generation.