D0.3-0036 studies on the ionospheric divergent hall current

Yoshikawa, A.; Yumoto, K.

doi:10.1016/s0273-1177(99)90163-1

Cited by 1 publication

(2 citation statements)

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“…The electrostatic ionosphere means dE rot ion (t) = 0 in the ionospheric current. Using (2), the expression of reflection coefficient of shear Alfvén waves at the electrostatic ionosphere: R A (0) = (AE A À AE P )/ (AE A + AE P ) [Scholer, 1970], and the mode conversion ratio from the rotational electric field to the divergent electric field, MC rot!div = AE H /(AE A + AE P ) [Yoshikawa andItonaga, 1996, 2000]…”

Section: Formulationmentioning

confidence: 99%

“…However, electrostatic conditions would be broken down for geomagnetic pulsations of which frequency is grater than those of Pc3–4 ranges [ Yoshikawa and Itonaga , 2000]. Some theoretical analyses suggest that the finite inductive rotational electric field in the ionosphere causes another type of shielding effect on δ b ⟂G for high‐conducting ionosheric condition or for high‐frequency oscillation, which is different from the ASE [ Yoshikawa , 1998; Yoshikawa and Itonaga , 2000; Nakata et al , 2000; Pilipenko et al , 2000]. However, in their treatment based on the homogeneous time‐dependent source field of exp(−iωt), the physical quantities derived from the inductive processes were mixed with that of direct response, and it is difficult to separate their relative contribution to the time‐change phenomena.…”

Section: Introductionmentioning

confidence: 99%

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Hall‐induced inductive shielding effect on geomagnetic pulsations

Yoshikawa

Obana

Shinohara

et al. 2002

Geophysical Research Letters

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A new formula describing the inductive response of the magnetosphere‐ionosphere‐atmosphere‐Earth electromagnetic coupled system to the time development of the field‐aligned current (FAC) source‐field is developed. Using this new formula, the Hall‐induced inductive shielding effect (ISE) on geomagnetic pulsation is investigated. The ISE is caused by the reduction of the amplitude of total rotational current because of the generation of “inductive” rotational current by the inductive part of ionospheric divergent electric field, which originates the existence of divergent Hall current. It will be shown that the ISE is more efficient for high‐frequency pulsations, large horizontal scale phenomena and high‐conducting ionospheric conditions. Quantitative analysis strongly suggests that the ionospheric conductivity in the dayside hemisphere can easily reach and sometimes exceed the turning point of geomagnetic pulsations of which frequencies are in the Pc 3 ∼ 4 pulsations range.

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Section: Formulationmentioning

confidence: 99%