[P-EM10] Dynamics of Magnetosphere and Ionosphere

[PEM10-P13] Ionospheric role in the development of the M-I convection system: generation of Alfvénic disturbances from the ionospheric convection field deformed by conductance non-uniformity

*Aoi Nakamizo¹, Akimasa Yoshikawa², Hiroyuki Nakata³, Keiichiro Fukazawa⁴, Takashi Tanaka⁵ (1.National Institute of Information and Communications Technology (NICT), 2.Faculty of Science, Kyushu University, 3.Graduate School of Engineering, Chiba University, 4.Academic Center for Computing and Media Studies, Kyoto University, 5.International Research Center for Space and Planetary Environmental Science, , Kyushu University)

Keywords:magnetosphere-ionosphere coupling, magnetosphere MHD simulation

We investigate how the ionosphere affects the magnetosphere by using a global magnetosphere MHD model.
First, we perform the simulation with the widely used conventional M-I coupling scheme.

We simulate the uniform and non-uniform ionospheric Hall conductance distribution cases. By using the Walén Separation [Yoshikawa et al., 2011], we separate the simulated disturbance field into the components propagating into/away from the inner boundary (Alfvénic disturbances). In the cases of non-uniform Hall conductance, the Alfvénic disturbances propagate dawn-dusk asymmetrically between the magnetosphere and ionosphere, resulting the dawn-dusk asymmetric magnetospheric convection field, including a Harang-like structure.
The result indicates that the ionosphere plays an active role in the configuration and dynamics of the global magnetosphere due to its non-uniform conductance distribution, as suggested by Nakamizo and Yoshikawa [2019].

In order to precisely investigate the role of the ionosphere, we are implementing an advanced M-I coupling scheme, Alfvénic Coupling [Yoshikawa et al., 2010] into the MHD model. We will show the results of the new coupling and compare them with that of the conventional coupling.