| 赤道反向电射流中不均匀性的对流放大特性及对某些观测特性的解释 |
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| 引用本文： | 涂传诒.赤道反向电射流中不均匀性的对流放大特性及对某些观测特性的解释[J].空间科学学报,1986,6(4):274-280. |
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| 作者姓名： | 涂传诒 |
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| 作者单位： | 北京大学地球物理系 |
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| 摘 要： | 本文分析了反向赤道电射流条件下的不均匀性的对流放大特性。根据电射流不稳定性的线性理论,对一个分层均匀的电射流的模式的数值计算表明:在反向电射流条件下,电射流不均匀性有如下的特性:在波的传播过程中,在上电射流区内,波矢向下旋转,在下电射流区内,波矢向上旋转;在驱动电场ED数值相同的情况下,反向电射流条件下的射线路径积分增长率r比正常电射流情况的要小得多。这是由于波的群速度方向是向下的,而电子密度梯度起稳定化作用。对于电子密度的特征长度LN=6km和│ED│=0.8mV/m,波长λ=10m,高度h≥105km,有r<20。在这一高度范围,波可能是不饱和的,增大LN,使波在h=105km饱和的临界电场│ED│值减小。上述计算结果可解释某些在反向电射流条件下,在Addis-Ababa观测到的10m波长雷达回波的特性。
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| 收稿时间： | 1984-01-12 |
Convective Amplification of Irregularities in the Counter Equatorial Electrojet and Explanations of Some Observed Properties |
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| Affiliation: | Department of Geophysics, Peking University |
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| Abstract: | The wave propagation and refraction of type "O" irregularities in the counter-electrojet conditions is investigated with a model electrojet in terms of the linear theory of the electrojet instability. Waves propagating with the electrons rotate their wave vectors downwards in the upper electrojet and upward in the lower electrojet. The ray-path integrated growth is much smaller than that in electrojet conditions for the same values of driven electric field |ED| because the vertical component of group velocity is downward during the day and the electron density gradient is stabilizing. For the electron density characteristic length LN = 6km and |ED| = 0.8 mV/m, the integrated growth for wave length λ= 10m is less than 20 for altitudes h≥ 105 km. In these altitude range, waves may be not saturated. With increasing LN, the value of |ED| for waves still being linear at altitudes h ≥ 105 km decreases. The characteristics of the convective amplification mentioned above may be associated with some of the properties of the irregularities in the counter equatorial electrojet observed at Addis-Ababa in 1977 (reference6] ). |
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