摘要
本文在用MHD理论研究等离子体束流不稳定性时发现:在电子等离子体频率附近可以激发出宽频带电磁波,其时间尺度、方向性、相对带宽、偏振特性及谐波结构等理论预期,在典型的日冕参数下,和米波段太阳射电Ⅲ型爆发的观测结果基本吻合.这一机制还可避免经典的等离子体辐射理论中由Langmuir波转换成横电磁波的效率较低的主要困难.
The plasma beam instabilities are studied on the basis of MHD theory in this paper. It is found that the electromagnetic waves with b oad bandwidth may be directly excited around the electron plasma frequency. The time scale, directionality, relative bandwidth, polarization and harmonic structures are predicted theoretically for typical coronal condition, which are consistent with the observations of solar type HI radio bursts at meter band. This model may also solve the main discrepancy of low efficiency of the transformation of Langmuir waves in the classical explanation for plasma emissions.
基金
国家自然科学基金
