高纬极区电离层离子声波谱线增强事件的研究

Event of the enhanced ion acoustic line spectra in the high-latitude auroral ionosphere

通过对子午扫描光度计以及欧洲斯瓦尔巴特群岛非相干散射雷达2004年1月22日的数据分析,发现非相干散射谱中出现的离子声波谱线增强发生在红色极光散射的区域内或附近,光学数据表明红色极光散射强度范围为4~32kR,而在发生离子声波谱线的自然增强现象时红色极光散射强度水平高于15kR.因此,极光粒子沉降与离子声波谱线增强具有一定的相关性.基于场向电流不稳定性模型,对发生离子声波谱线增强的雷达数据进行了分析,反演得到的场向电流量级达到了mAm-2量级.进一步采用修正的场向电流不稳定解释离子声波谱线时,由于场向热流的引入,反演得到的场向电流会变的更大.

The data of meridian scanning photometer and EISCAT Svalbard Radar on Jan 22 2004 are analyzed,and the results shows that naturally enhanced ion acoustic lines of incoherent scatter spectra in the vicinity of the red auroral forms.The meridian scanning photometer observations from Longyearbyen near ESR site shows red auroral emission from 4to 32 kR.The value of the emission density is more than 15 kR when naturally enhanced ion acoustic lines happen.There exists the good correlation of particle precipitation and naturally enhanced ion acoustic lines.According to the field-aligned current model,the data of the naturally enhanced ion acoustic lines are analyzed.The field-aligned current density are obtained by reversion,the magnitude of the values is to mAm-2.The values of the field-aligned current density become small based on the modified field-aligned current model due to introducing the term of the field-aligned heat flow.