Kiyohumi YUMOTO
Space Environment Research
Center (SERC)
Kyushu
University, Japan
November 2005
This document
briefly outlines the forwarding-looking plans of this research center, Space Environment Research Center
(SERC). SERC seeks partners in
developing nations to expand our global monitoring of the earth's magnetic
field. This document mentions the
nations where our instrument (called MAGDAS) has already been successfully
deployed. Until now, deployment
largely has occurred at points south and north of Japan, not east and west of
Japan.
In the new
year (i.e., Year 2006) and beyond, SERC would like to deploy its magnetometer
(MAGDAS) at points near the geomagnetic equator, circumnavigating the
globe. The new points we are
seeking are located at:
*
Peru
*
Brazil (near EUS point)
*
Cote-D'ivoire
*
Nigeria
*
Ethiopia
*
India
*
Thailand (Phuket)
*
The Philippines
*
Yap Island (part of the Federated
States of Micronesia)
* Ponape
* Christmas Island
Additionally,
we are seeking some new low-latitude points:
* Mexico
* Trinidad
* Brazil (Santa Maria)
* South Africa
* Italy
* Georgia (near Russia)
Our
needs:
As
mentioned above, SERC seeks partners in developing nations to carry out our sun-space-earth research using
state-of-the-art technology.
(Our MAGDAS, described in more detail below, represents state-of-the-art
technology. It can be readily
deployed in inhospitable locations, and send its data to SERC via the Internet
in a near real-time manner. In
this respect, MAGDAS is unique. It
was designed from accumulated know-how from vast field experience around the
world over many years.)
Partners
must provide the following:
-
One IP (Internet Protocol) connection. The load is small (80kbs).
-
A location away from electromagnetic noise sources (such as
gasoline and electric motors of all kinds). Vehicular traffic should be more than 200m away.
-
A small amount of maintenance (average would be about one
hour per week).
-
Electricity (60W or so).
-
Security. Theft
of any component of MAGDAS is not desirable.
-
Finally, a ten-year commitment as a partner.
In
return, the overseas partner will learn a great deal more about the
international scientific community, and how it operates, how it plans, how it
grows, how it exploits new technology (such as the Internet), how it educates
the next generation of researchers, how it helps mankind, and how it secures
funding from organizations that have funds.
Below
is more information on our research effort.
(1)
The instrument and network (collectively called MAGDAS):
The Circum-pan Pacific
Magnetometer Network (CPMN) was constructed by Kyushu University
in collaboration with about 30 international organizations along the 210°magnetic meridian and magnetic equator during
the international Solar Terrestrial Energy Program
(STEP) period (1990-1997) as shown in Figure 1. For space weather research and applications, the
Kyushu University group is now deploying a new real-time MAGDAS (MAGnetic
Data Acquisition System) in the CPMN region, and the FM-CW radar network along the 210°magnetic meridian. Fifty new
fluxgate-type magnetometers (shown in Figure 2) and their data acquisition
systems send data from overseas sites to Fukuoka, Japan. Before deployment, each instrument is
rigorously tested at the Space Environment
research Center (SERC), Kyushu University.
The new magnetometer system consists of a 3-axial
ring-core sensors, fluxgate-type magnetometer, data logging/transferring unit,
and power supply. Magnetic field digital data (H+δH, D+δD, Z+δZ, F+δF) are obtained at the sampling rate of 1/16 seconds, and then the
averaged data are transferred from overseas stations to SERC in near real
time. The ambient magnetic field,
expressed by horizontal (H), declination (D), and vertical (Z) components, are
digitized by using the field-canceling coils for the dynamic range of ±64,000nT/16bit. The total
field (F+δF) is estimated from the H+δH, D+δD, and Z+δZ components. The resolution
of MAGDAS data are 0.061 nT/LSB and 0.031 nT/LSB for ±2,000 nT and ±1,000 nT range, respectively.
The estimated noise level of the MAGDAS magnetometers is 0.02
nTp-p. The long-term inclinations
(I) of the sensor axes are measured by two tiltmeters with 0.2 arc-sec
resolution. The temperature (T) inside the sensor head is also measured. GPS signals are received to adjust the
standard time inside the data logger/transfer unit. These data are logged into the Compact Flash Memory Card of
1 GB. The total weight of the compact
MAGDAS magnetometer system is less than 15 kg. (all shown in Fig.3).
The instrument is entirely self-contained, except for power and IP
needs.
(2) People involved in the MAGDAS
Project:
Project
Leader: Prof. Dr. Kiyohumi Yumoto
Japan
Kyushu
University
Prof. K. Yumoto , Dr. H. Kawano, Dr. A.
Yoshikawa, Dr. M. Shinohara, Dr. T. Uozumi,
Dr. Y. Obana, Dr. S.
Abe, and Mr. G. Maeda
Tohoku
Institute of Technology
Dr. M. Seto, and Mr.
Y. Kitamura
Taiwan
National
Central University
Prof. Tiger
Liu, Mr. SW Chen
Philippines
Coast
and Geodetic Survey Department, National Mapping and Resource Information
Authority
Commodore
RODOLFO M. AGATON, Dr. I. Nakagawa (JICA), Mr. Alex Algaba and
Mr. Carter
Luma-ang
Cagayan
State University (northern Philippines)
Prof. Joseph
B. Acorda, Mr. Manuel P. Rosete, Dr. Diosdado B. Dimalanta, and
Ms Maria
Jackie Lou A. Liban
University
of San Carlos (at Cebu)
Dr.
Roland Emerito S. Otadoy, Mr. Erwin Orosco
Magnetic
Observatory (at Davao), Ateneo de Manila University Campus
Fr.
Badillo Victor L., Mr. Efren Morales
Indonesia
Space
Science Application Center , LAPAN, Bandung
Drs. Suratno, Mr Mamat Ruhimat
Badan
Meteorolog dan Geofisika, MGA, Manado
Drs. Subardio,
Potential
Geophysics and Time Signals, Meteorological and Geophysical Agency of Indonesia
Muhammad
Husni
Australia
IPS
Radio & Space Services
Dr David Cole, Dr Phil Wilkinson, Dr
Richard Marshall, Dr Dave Neudegg, Dr Mike Hyde
Mr.
George Goldstone
CSIRO,
Wildlife & Ecology, TERC, Darwin
Mr. Tony
Hertog
Australian Antarctic Division (in charge of MacQuarie Island)
Lloyd Symons, Dr. Ray Morris
La Trobe University, Victoria
Prof. Peter L. Dyson
Russia
Institute of Cosmophysical Researches and
Radio Wave Propagation (IKIR), FEB
RAS
Prof. Boris Shevtsov
Institute
of Cosmophysical Research and Aeronomics (IKFIA), Siberian Division RAS
Dr. S.-I.
Soloveyev, Dr. Dmitry Baishev
Pacific
Ocean Institute, FEB RAS
Dr. Valerian
Nikiforov
USA
Institute
of Geophysics and Planetary Physics, UCLA
Dr. Peter Chi
Minnesota
State University
Dr. Linda Winkler
(3) Scientific objectives of the MAGDAS
Project:
The MAGDAS system is
now being deployed in order to carry out space
weather studies during the 2005-2008 time frame. We need to clarify the dynamics
of geospace plasma changes during magnetic storms and auroral substorms, the
electro-magnetic response of iono-magnetosphere to various solar wind changes,
and the penetration and propagation mechanisms of DP2-ULF range disturbances
from the solar wind region into the equatorial ionosphere. The ordinary data can be
used for studies of long-term variations, e.g. magnetic storm, auroral
substorms, Sq, etc., while the induction-type will be useful for studies of ULF
waves, transient and impulsive phenomena.
By using this new MAGDAS data, we can conduct real-time monitoring and modeling of (1) the
global 3-dimensional current system and (2) the ambient plasma density for understanding
the electromagnetic and plasma environment changes in the geospace.
3.1.
Global 3-D current system
We will make the ionospheric equivalent current pattern every day using
the MAGDAS data. At high latitudes the ionospheric currents are joined with field-aligned
currents (FAC) from the solar wind region into the magnetosphere, and
the electro-dynamics is dominated by the influences of solar wind-magnetosphere
interaction processes. The total
current flow is on the order of 107 A. On the other hand, the ionospheric current at middle and low
latitudes is generated by the ionospheric wind dynamo, which produces global
current vortices on the dayside ionosphere, i.e., counterclockwise in the
northern hemisphere and clockwise in the southern hemisphere. The total current flow in each vortex
is order of 105 A.
There are strong electric fields
at high latitudes, on the order of several tens of millivolts per meter or
more, depending on the magnetic activity.
At middle and low latitudes electric fields are considerably smaller,
typically a few millivolts per meter during magnetically quiet periods. During magnetic active periods the part
of strong electric fields at high latitude can penetrate into middle and low
latitudes, and then the global ionospheric current pattern must be re-organized
strongly. In reality the current
and electric fields at all latitudes are coupled, although those at high, and
middle and low latitudes have been often considered separately. By using the MAGDAS ionospheric current
pattern, the global electromagnetic coupling processes at all latitudes can be
clarified during the CAWSES.
3.2. Ambient plasma
density
The field line resonance (FLR)
oscillations in the Earth's magnetosphere are excited by external source waves,
and are so-called as ultra low frequency (ULF) waves. The amplitude of H-component magnetic variations observed at
the ground stations reaches a maximum at the resonant point, and that its phase
jumps by 180 degrees across the resonant point. The eigen-frequency of FLR oscillations is dependent upon
the ambient plasma density and the magnetic field intensity in the region of geospace
threaded by the field line, and the length of the line of force. When we
observe the eigen-frequency of FLR and assume models for the latitude profiles
of the magnetic field and the plasma density (with the equatorial density as a
free parameter), we can estimate the plasma mass density in the magnetosphere. Therefore, the FLR oscillations are
useful for monitoring temporal and spatial variations in the magnetospheric plasma
density. By using ground-based network
observations, we can identify the FLR phenomena and measure the fundamental
field-line eigen-frequency by applying the dual-station H-power ratio method
and the cross-phase method, which have been established to identify the FLR properties.
We have installed MAGDAS magnetometers at several pair
stations along the 210°magnetic meridian, and we are currently observing magnetic
FLR pulsations. Each pair station
is separated in latitude by ~100 km. MAGDAS data will be analyzed by using two methods, i.e., the
amplitude-ratio method and the cross-phase method. As a result, we identify the FLR events and measure their eigen-frequencies,
providing the plasma density varying with time. By using these results, we will
discuss temporary variations of the ambient plasma density and the location of
the plasmapause during magnetic
storms and auroral substorms.
Fig. 1. MAGDAS/CPMN (MAGnetic
Data Acqusition System/Circum-pan Pacific Magnetometer
Network) system of the SERC, Kyushu Univ.
Fig.
2. The components of M AGDAS/CPMN
magnetometer system for real-time data acquisition.
Fig. 3. MAGDAS magnetometer set
End of document.