MAGDAS/CPMN PROJECT FOR LITHO-SPACE WEATHER DURING IHY/ISWI (2007-2012)

  1. Space Environment Research Center, Kyushu University, Japan

The Space Environment Research Center (SERC), Kyushu University deployed the MAGnetic Data Acqusi-
tion System (MAGDAS) at 50 stations along the 210- and 96-degree magnetic meridians (MM) and the magnetic
Dip equator, and three FM-CW radars along the 210-degree MM during the International Heliophysical Year
(IHY) period of 2005-2009 (see http://magdas.serc.kyushu-u.ac.jp/ and http://magdas2.serc.kyushu-u.ac.jp/).
The goal of MAGDAS project is to become the most comprehensive ground-based monitoring system of the
earth’s magnetic field. It does not compete with space-based observation. Rather, this ground-based network
complements observation from space. To properly study solar-terrestrial events, data from both are required.
This project intends to get the MAGDAS network fully operational and provide data for studies on Litho-space
Weather. By analyzing these new MAGDAS data, we can perform a real-time monitoring and modeling of the
ambient plasma mass density and the global (e.g. Sq, EEJ) current system for understanding the plasma and
electromagnetic environment changes in geospace and lithosphere during helio-magnetospheric storms. In order
to examine the propagation mechanisms of transient disturbances, i.e., sc/si, Pi 2, and DP2, relations of iono-
spheric electric and magnetic fields are investigated by analyzing the Doppler data of our FM-CW ionospheric
radar and the MAGDAS magnetic data. A new EE-index (EDst, EU, and EL) was also proposed by SERC
for real-time and long-term geospace monitoring. The basic algorithm to obtain EE-index was constructed by
Uozumi et al. (2008). EU and EL mainly represent the range of the EEJ (equatorial electrojet) and CEJ (equa-
torial counter electrojet) components, respectively. The baseline levels of EU and EL are obtained by averaging
the H-component magnetic variations observed at the nightside (LT = 18-06) MAGDAS/CPMN (Circum-pan
Pacific Magnetometer Network) stations along the magnetic equator. The baseline value is defined as EDst and
its variations are found to be similar to those of Dst. We examined relationships among the EEJ amplitude,
the F10.7 solar radiation flux, the solar wind parameter, Ap-index and the ionospheric conductivity. It is found
that the intensity of the EEJ depends on the 11-years solar activity. The semi-annual EEJ oscillation is caused
by changes in the ionosphere dynamo and not by changes in the ionospheric conductivity. The 14.5-day EEJ
oscillation may be caused by semi-monthly lunar tidal waves. The short-term EEJ variations are also controlled
by the interplanetary electric field (Ey = - VSW x BIMF). By using the MAGDAS/CPMN system and FM-CW
radar array, we could obtain the following results; (1) Imaging of global 3-D current system, (2) Annual and
semi-annual Sq and EEJ current variations, (3) A new EE-index and its long-term variation, (4) Estimation of
plasma mass density, (5) Latitudinal dependence of Pc 3-4 amplitudes along 96o MM and Pi 2 along 210o MM,
(6) Ionospheric electric fields of DP-2, sc, Pi2, and Pc 5 observations by FM-CW radar, and (7) anomalous
magnetic daily and ULF variations associated with the great earthquakes observed near the MGDAS/CPMN
stations. In this paper, we will review the several scientific results obtained by MAGDAS project, and intro-
duce a coordinated near-earth JAXA satellite (ETS-VIII, QZS) and MAGDAS observations in Siberia, where
10 new MAGDAS magnetometers will be installed near the foot points of the Quasi-Zenith Satellite (QZS) for
space weather, and an international collaboration (Asian network) to establish the short-term EQ prediction
in southern Sumatra, Indonesia, where 10 ULF-EM(MT) sites will be constructed in 2010 with inter-sensor
distance of 100-200 km, during the International Space Weather Initiative (ISWI) period of 2010-2012.