均匀等离子体中共振波粒不稳定性的准线性扩散模型
A Quasi-Linear Diffusion Model for Resonant Wave-Particle Instability in Homogeneous Plasma
摘要：
本文建立了一个描述准中性等离子体中广义波粒不稳定性的模型。我们分析了准线性扩散方程的粒子表示为高斯波包的任意不稳定和共振波模式，允许相对于背景磁场的任意方向的传播。我们发现，本地化的能量密度的高斯波包决定的速度空间范围内，占主导地位的波粒不稳定性和抵消阻尼的贡献是有效的。此外，我们推导出一个关系描述的扩散轨迹的共振粒子在速度空间的作用下，这样的波粒不稳定性和阻尼之间的相互作用。对于我们的理论模型的数值计算，我们开发了一种基于Crank-Nicolson格式的数学方法来求解完全准线性扩散方程。我们的数值分析解决了主导波粒不稳定性和抵消阻尼的作用下的速度分布函数的时间演化，并与我们的理论描述显示出良好的一致性。作为一个应用，我们使用我们的模型来研究斜快磁声/哨声不稳定性，这是作为一种散射机制的strahl电子在太阳风提出的。此外，我们还数值求解了Fokker-Planck方程，计算了在斜快磁声/哨声不稳定性的无碰撞作用下，在与芯部电子和质子的库仑碰撞作用下，电子-散射分布函数的时间演化.
英文摘要：
In this paper, we develop a model to describe the generalized wave-particle instability in a quasi-neutral plasma. We analyze the quasi-linear diffusion equation for particles by expressing an arbitrary unstable and resonant wave mode as a Gaussian wave packet, allowing for an arbitrary direction of propagation with respect to the background magnetic field. We show that the localized energy density of the Gaussian wave packet determines the velocity-space range in which the dominant wave-particle instability and counter-acting damping contributions are effective. Moreover, we derive a relation describing the diffusive trajectories of resonant particles in velocity space under the action of such an interplay between the wave-particle instability and damping. For the numerical computation of our theoretical model, we develop a mathematical approach based on the Crank-Nicolson scheme to solve the full quasi-linear diffusion equation. Our numerical analysis solves the time evolution of the velocity distribution function under the action of a dominant wave-particle instability and counteracting damping and shows a good agreement with our theoretical description. As an application, we use our model to study the oblique fast-magnetosonic/whistler instability, which is proposed as a scattering mechanism for strahl electrons in the solar wind. In addition, we numerically solve the full Fokker-Planck equation to compute the time evolution of the electron-strahl distribution function under the action of Coulomb collisions with core electrons and protons after the collisionless action of the oblique fast-magnetosonic/whistler instability.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
