The magnetic field variations observed during the June 21, 2001, Total Solar Eclipse

*Yoshimasa Tanaka[1] ,Akimasa Yoshikawa [1]
Kiyohumi Yumoto [1],P. R. Sutcliffe [2],A. Meloni [3]
P. Palangio [3]
Department of Earth and Planetary Sciences, Kyushu University[1]
Hermanus Magnetic Observatory, South Africa[2]
Istituto Nazionale di Geofisica, Italy[3]

We conducted the magnetic field observation of the total solar eclipse in Africa on June 21, 2001. We installed the magnetometers at Lusaka (LSK, Mlat=-26.1 degrees, Mlon=98.7 degrees) and Chirundu (CRD, Mlat=- 26.8 degrees, Mlon=97.8 degrees), Zambia, which are separated by 70 km in the magnetic latitude. We study the spatial scale of the solar eclipse effect on the Sq magnetic variations by using the data obtained from Hermanus (HER, South Africa; Mlat=-42.1 degrees, Mlon=82.3 degrees) and Laquila (LAQ, Mlat=36.3 degrees, Mlon=87.6 degrees) of the CPMN, in addition to LSK and CRD. As a result, the magnetic disturbances were observed in the Sq magnetic variation in the D component at LSK and CHD during the solar eclipse.

We conducted the magnetic field observation of the total solar eclipse in Africa on June 21, 2001. There are two principal purposes in this observation; one is to investigate the solar eclipse effect on the Sq magnetic field variations in detail, and the other is to study the eclipse effect on the frequency of Pc 3 pulsations. It is well known that the electron density and the conductivity in the ionosphere decrease during the solar eclipse, which results in the deformation of the ionospheric current pattern for the Sq magnetic variations. Therefore, the magnetic disturbances can be observed on the ground during the solar eclipse. By the magnetic field observations of the solar eclipse in Europe on August 11, 1999, we have found that the magnetic disturbances were observed at the stations aligned to the eclipse path during the solar eclipse and they showed the time difference corresponding to the eclipse time. Furthermore, the temporal variation of the electron density in the ionosphere may cause the temporal variation of the resonance frequency of Pc 3 pulsations.
In order to determine the resonance frequency of Pc 3 pulsations, the dual-station H ratio and the phase gradient technique is very useful. Therefore, we installed the magnetometers at Lusaka (LSK, Mlat=-26.1 degrees, Mlon=98.7 degrees) and Chirundu (CRD, Mlat=-26.8 degrees, Mlon=97.8 degrees), Zambia, which are separated by 70 km in the magnetic latitude. We also study the spatial scale of the solar eclipse effect on the Sq magnetic variations by using the data obtained from Hermanus (HER, South Africa; Mlat=- 42.1 degrees, Mlon=82.3 degrees) and Laquila (LAQ, Mlat=36.3 degrees, Mlon=87.6 degrees) of the CPMN, in addition to LSK and CRD. As a result, the magnetic disturbances were observed in the Sq magnetic variation in the D component at LSK and CHD during the solar eclipse. The sense of the magnetic disturbances is consistent with the decrease of the ionospheric current for Sq magnetic variation. On the other hand, Pc 3 pulsations did not appear during the solar eclipse.