Toshihiko Iyemori

TL;DR: In this paper, the longitudinally symmetric and asymmetric components of the geomagnetic field were derived from 10 mid-latitude stations to examine the storm-time magnetospheric current system, and the asymmetry in D component suggests that net downward and upward field-aligned currents exist in the morning sector and from the evening to the early morning sector, respectively, when the IMF is southward.

TL;DR: In this paper, the existence of a sharp break in the power spectrum of AE at about 5 hours is demonstrated and several possible explanations of the nonlinear response of AE to the IMF Bs driver are briefly discussed, including variable ionospheric conductivity (increasing with Bs) and several AE saturation mechanisms for the low frequency regime.

TL;DR: In this paper, a comprehensive study of traveling compression regions (TCRs) in the distant magnetotail was conducted, and strong support was obtained for the interpretation of TCRs as large-scale compressions of the lobes caused by the rapid downtail motion of plasmoids.

TL;DR: In this paper, the impulse response of the geomagnetic indices (Dst, AL, AU and AE) to the interplanetary magnetic field southward component (IMF-Bz) is calculated on the assumption that the magnetosphere acts as a linear system.

TL;DR: In this paper, the formation of a closed ring current from a partial ring current is examined quantitatively by a particle trajectory tracing method using a model with monochromatic energy and pitch angle distribution using a dipole magnetic field with a timevarying electric field.