用粒子模拟方法研究离子声波

<正>向传播朗缪尔波被离子声波散射是太阳射电Ⅲ型暴基波和谐波激发的重要过程.使用粒子模拟方法对电子束流激发朗缪尔波的过程进行了模拟,同时对产生的反向朗缪尔波、朗缪尔波2次谐波和朗缪尔波通过非线性过程产生的离子声波的性质进行了分析研究.为了更好地研究离子声波,模拟时单独计算了由离子扰动引起的电场.模拟计算了不同初始参数下产生的离子声波强度,发现离子的温度和质量对离子声波的产生有重要作用,验证了反向朗缪尔波与离子声波的相关性.同时在模拟中验证了朗缪尔波的衰变过程,确认了离子声波对反向朗缪尔波的放大作用.

Study of the Ion Sound Wave by Particle-in-cell Simulation

The process of the forward Langmuir waves scatted by ion sound waves is very important for the fundamental and harmonic emission of the type III solar radio bursts. We use the particle in cell simulation to study the property of the ion sound waves during the plasma emission process. We calculate the electric field only excited by ions during the simulation to study the evolution of the ion sound waves. We calculate the energy of ion sound waves with different parameters, and find that the temperature and mass of ion are important to enlarging the ion sound waves. Also, we verify the relationship between the ion sound waves and the backward propagating Langmuir waves due to the energy ratio of forward Langmuir waves and ion sound waves. Both the waves decay and scattered process have been confirmed. Therefore, we find the ion sound waves have a positive contribution to backward Langmuir waves.