- 作者: 林崇安
- 作者服務機構: 國立中央大學大氣物理研究所
- 中文摘要: 本文依據CGL方程式來研究磁層副暴開始時產生在電漿片之夜問磁性流體波。此中,考慮了速度切及黏滯效應,先導出此MHD波之頻散關係式,並得知由黏滯效應產生之阻尼率隨波長之增加而急降。在考慮波長很長及受阻尼效應很小的快速磁聲波下,本研究得出頻散關係式之一數值解。此中得知由於速度切之存在,使得快速磁聲波滋長。計算所得之快速波特性符合地磁特低緯度地區夜間所測的MHD波之性質。
- 英文摘要: An approach based on CGL equations is proposed to investigate the nighttime MHD waves generatedin the plasma sheet during magnetospheric substorm onsets. The velocity shear and viscous effect of theplasma flow are taken into account. A general dispersion relation of the MHD waves is derived. It is foundthat the damping rate due to viscosity decreases rapidly with wavelength. A numerical solution of thedispersion relation is presented by restricting to fast magnetosonic waves with very long wavelength andlow viscosity. It is found that the existence of the velocity shear will excite the fast magnetosonic waveto grow. The computed characteristics of the fast wave are consistent with the nighttime MHD wavesobserved in geomagnetic very low latitudes.
- 中文關鍵字: MHD waves; viscosity; velocity shear; substorm onsets
- 英文關鍵字: --