高频加热中低纬电离层激励不稳定性研究  

Research of ionospheric instability excited in mid and low latitudes HF heating

作　　者：邓峰[1] 赵正予[1] 周晨[1] 黄建[1] 

机构地区：[1]武汉大学电子信息学院,武汉430079

出　　处：《地球物理学报》2010年第1期10-21,共12页Chinese Journal of Geophysics

基　　金：国家高技术研究发展计划(2007AA809302)资助

摘　　要：高频泵波加热电离层实验二维数值模拟结果显示,虽然背景电离层状态能够明显影响模拟加热结果,但是在大部分平静电离层状态下,模拟加热一段时间后,加热区域内电子浓度、电子温度会趋于稳定,这一结论已为实验所证实.然而部分模拟结果显示,当电离层电子浓度、电子温度空间结构满足一定条件后,过密加热中泵波反射区域,电子浓度、电子温度在加热机开关机后将产生不稳定的时空效果.激发该不稳定性的正反馈过程如下:当泵波反射区域内电子温度受到泵波加热上升后,其引起的等离子体膨胀导致该区域内电子浓度减小,受到电子温度、电子浓度变化的共同影响,电子能量方程中由于电子-离子碰撞导致的电子能量损失项减小,电子温度将进一步升高,一种正反馈机制建立.最后得到以下结论,当电离层电子温度剖面呈明显的双峰结构,被加热区域内电子温度较高,且电子-离子碰撞引起能量损失项成为电子主要的能量损失项后,一种不稳定性被激发,加热将产生更明显的电子浓度、电子温度的变化.以上条件在下午电离层更容易被满足.The results of 2D simulation of Heigh Frequency （HF） ionospheric heating around the reflection height shows that in most ionospheric initial condition, the modeling result of Te and ne will tend to stabilize. But some simulation results show that if some conditions about the space-structures of ne and Te are satisfied, the ne and Te would not be stable after turning on or off of the HF heating equipment, some instability mechanism was excited. This article introduces the simulation result of ionospheric heating first, and then calculates every item of electron energy equation in the simulation. The process causing instability is as follows： when the Te of the region above the pump reflection height increases intensely, the ne will decrease instead, the change of ne and Te would cause decrease of the energy loss due to electron-ion collision, after that the Te would increase further, a unstable mechanism has set up. The conclusion is that if the profile of Te is double-hump, the Te of the region above the reflection height is high enough and electron-ion collision is the main way of lost energy of electron, this instability will be excited.

关 键 词：高频加热 中低纬电离层 不稳定性 数值模拟 

分 类 号：P352[天文地球—空间物理学]