THEORY OF A WEAKLY TURBULENT PLASMA
THEORY OF A WEAKLY TURBULENT PLASMA
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DOI：
10.1007/978-1-4615-7799-7_3
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发表时间：
1967
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影响因子：
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通讯作者：
A. Vedenov
中科院分区：
文献类型：
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作者：
A. Vedenov
等离子体的一个特征是存在集体振荡或等离子体波（等离子体激元）的频谱。这些波的传播频率和速度由波矢量和等离子体的总体参数（如密度、平均传播速度、磁场等）决定，这种情况反映了等离子体中所有粒子都参与等离子体振荡的事实。然而，当考察振荡的阻尼（或增长）时，情况就不同了。阻尼（生长）是由相空间中粒子分布的“精细细节”决定的，例如，由速度分布函数的导数决定；这种情况反映了共振粒子所起的特殊作用。e.满足以下条件的粒子：Wk-kv= nWH；n= D, 1,2，…；这里，wk和k是表征波的频率和波矢量，v是粒子速度，wH= eH/me)，这些粒子能够与波交换能量，因此可以放大或阻尼波。共振粒子在等离子体波的阻尼中所起的重要作用可以从以下事实中看出：在热力学平衡状态下，等离子体中以频率和波数k为特征的波的阻尼与电子分布函数f (v)在点v= Wk/k处的导数成正比；这一结果最早是由Landau[1]利用自洽场方程建立的[2,3]。
A characteristic feature of a plasma is the existence of a spectrum of cOllective oscillations or plasma waves (plasmons). The frequency and velocity of propagation of these waves are determined by the wave vector and by the gross parameters of the plasma such as the density, the mean velocity spread, the magnetic field, etc., and this situation is a reflection of the fact that all of the particles in the plasma are involved in the plasma oscillations. The situation is different, however, when one examines the damping (or growth) of the oscillations. Damping (growth) is determined by the" fine details" of the particle distribution in phase space, for example, by the derivative of the velocity distribution function; this situation reflects the specific role played by resonance particles 0. e., particles for which the following condition is satisfied: Wk-kv= nWH; n= D, 1, 2,...; here, wk and k are the frequency and wave vector that characterize the wave, v is the particle velocity, and wH= eH/me), These particles are capable of exchanging energy with the waves and can thus amplify or damp it.The important role played by resonance particles in the damping of plasma waves is evident from the fact that the damping of a wave characterized by frequency wand wave number k in a plasma in thermodynamic equilibrium is found to be proportional to the derivative of the electron distribution function f (v) taken at the point v= Wk/k; this result was first established by Landau [1] through the use of the self-consistent field equations [2, 3].