Japan Geoscience Union Meeting 2023

Presentation information

[E] Oral

P (Space and Planetary Sciences ) » P-EM Solar-Terrestrial Sciences, Space Electromagnetism & Space Environment

[P-EM15] Study of coupling processes in solar-terrestrial system

Fri. May 26, 2023 9:00 AM - 10:30 AM 101 (International Conference Hall, Makuhari Messe)

convener:Mamoru Yamamoto(Research Institute for Sustainable Humanosphere, Kyoto University), Yasunobu Ogawa(National Institute of Polar Research), Satonori Nozawa(Institute for Space-Earth Environmental Research, Nagoya University), Akimasa Yoshikawa(Department of Earth and Planetary Sciences, Kyushu University), Chairperson:Yasunobu Ogawa(National Institute of Polar Research), Satonori Nozawa(Institute for Space-Earth Environmental Research, Nagoya University)

10:00 AM - 10:15 AM

[PEM15-05] The Causality of Electromagnetic Channel Formation in the Ionosphere from Polar to Equatorial Regions

*Akimasa Yoshikawa1 (1.Department of Earth and Planetary Sciences, Kyushu University)

Keywords:Electromagnetic Channel Formation, ionospheric current, electromagnetic process

The formation of the global ionospheric current systems and their associated plasma dynamics are frequently discussed under the electrostatic approximation of plasma electrodynamics. Since the Poynting flux never across the equipotential line, it is impossible to provide electromagnetic energy from the source region to the loading region across the magnetic field line. And hence, to discuss causality for the evolution of the ionospheric current system, we need to take into account an electromagnetic process of the coupled system. To resolve this problem, we propose an electromagnetic coupling model from the polar to the equatorial ionosphere. In this model, ionospheric current produces Ampere force and generates the motion of plasma. The motion of plasma and associated mechanical processes excite electromotive force and the resultant electric field. The Curl of the electric field causes magnetic field disturbances and the evolution of ionospheric current. Therefore, causality for the evolution of electromagnetic energy and plasmas acceleration for expanding of the ionospheric current system has occurred at the wavefront region and/or conductivity gradient region. In this talk, we will discuss what type of plasma motion induces an electric field in the ionosphere, and how and where they produce magnetic field disturbances (hence the Ampere force) for an acceleration of plasma as a wave propagation process. Furthermore, we also discuss what kind of mechanical and electromagnetic processes have occurred at the conductivity gradient region, which becomes very important for the establishment of the geometrical structure of the ionospheric current system.