THE GENERATION MECHANISM OF SOLAR METRE-WAVE MOVING TYPE IV BURSTS
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摘要: 本文提出ⅣmA型爆发的一种模型,并且以l波与s波通过非线性相互作用转化为t波的过程l±st作为其辐射机制,对8个ⅣmA型爆发计算了辐射亮温度的谱,得到一些与观测符合较好的结果。本文提出的模型和辐射机制克服了原有的模型和回旋同步辐射机制的困难,比较合理地解释了ⅣmA型爆发的主要特征。本文还就Te=Ti和Te>>Ti两种条件下的等离子体辐射机制进行了讨论。Abstract: In this paper a new model and radiation mechanism of type IVmAbursts are presented.Plasma clouds ejected during the exposive phase of flare move upward inside a large magnetic arch,trapped nonthermal electrons (E≈100 KeV) with forward-cone gap distribution excite Langmuir wave.Under the condition Te>>Ti there should be ion-sound wave in the source.The electromagnetic transverse wave is produced through the nonlinear interaction between the two waves and the type IVmAburst takes place.The spectra of brightness temperature and their evolution for eight announced events are calculated and the results coincide with observations rather well.The other main characteristics of the bursts,such as polarization,life-time,the relation between the size and position of sources and frequencies etc.,are all explained more reasonably.The radiation processes under conditions Te=Ti and Te>>Ti are compared with one another.It is shown that the condition Te>>Ti is more probably true,so the main contribution to the radiation doesn't come from iou scattering,but from the nonlinear process l±s(这里有图片19820101-261-1.GIF)t.This conclusion is not only true for the type IVmAbursts,but also probably for some other types of solar radio bursts.
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