Ionospheric Feedback Instability in the Coupling of Magnetosphere-Ionosphere
WANG Xu-Yu1,2, CAO Jin-Bin1
1Laboratory of Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100080
2Physikalisckes Institut, University of Bern, Bern CH-3012, Switzerland
Ionospheric Feedback Instability in the Coupling of Magnetosphere-Ionosphere
WANG Xu-Yu1,2; CAO Jin-Bin1
1Laboratory of Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100080
2Physikalisckes Institut, University of Bern, Bern CH-3012, Switzerland
Abstract： The ionospheric feedback instability is discussed by using the
conductivity argument. We give an exact quantitative description to show that the free energy for this instability comes from the reduction of the Joule dissipation produced by the pre-existing convection electric field through self-consistent changes in ionization and conductivity due to Alfvénic perturbations in the ionosphere. By the over-reflection of Alfvén waves, the energy in the active ionosphere is pumped into the magnetosphere, which is contrary to the usual case whereby energy carried by Alfvén waves is deposited in the ionosphere by Joule dissipation. The ionospheric feedback enhances the electron E x B drift. The electron conductivity is controlled by the ion Perdersen conductivity rather than by the electrons Pedersen conductivity. We also provide a qualitative theoretical explanation to the intense aurora favoured by a lower ambient ionospheric conductivity in the ionospheric feedback instability.
WANG Xu-Yu; CAO Jin-Bin. Ionospheric Feedback Instability in the Coupling of Magnetosphere-Ionosphere[J]. 中国物理快报, 2003, 20(8): 1401-1404.
WANG Xu-Yu, CAO Jin-Bin. Ionospheric Feedback Instability in the Coupling of Magnetosphere-Ionosphere. Chin. Phys. Lett., 2003, 20(8): 1401-1404.
2003, Vol. 20 
