一种同步回旋激射不稳定性对电磁波的直接放大

DIRECT AMPLIFICATION OF ELECTROMAGNETIC WAVES BY A SYNCHROTRON MASER INSTABILITY

本文讨论了一种同步回旋激射不稳定性对电磁波的直接放大,它基于少量在速度空间具有空心分布的中等相对论性高能电子束与本底等离子体中本征电磁模的共振相互作用。主要关心的是的参数区域(ω_e为电子等离子体频率,Ω_e为电子回旋频率)。计算表明,若电子束的单能性很高,则不稳定性增长率比同样参数下由动力效应计算得出的增长率高若干个数量级,且最大增长率处在2ω_e附近。

Direct amplification of electromagnetic waves by a synchrotron maser instability is discussed, which is based on the rssonant interaction of a dilute moderately relativistic electrons with monoenergetic hollow-beam distribution and the elctromagnetic eigenmode ia background plasma. We are mainly conce rned about the parameter regime of |ωe/Ωθ| 10, whereωe is the electron conceplasma frequency, and Ωe is the electron cyclotron frequency. It is shown that for monoenergetic distribution of high energy electrons, the growth rate of this instability is several orders of inagnetude higher than that calculated from the kinetic interaction model while parameters involved are comparable. It is also found that the maximun growth rates appear at a frequency of about 2ωe.