future china geomagnetism satellite mission (cgs)
Post on 31-Dec-2015
39 Views
Preview:
DESCRIPTION
TRANSCRIPT
Future China Geomagnetism Satellite
Mission (CGS)
Aimin Du
Institute of Geology and Geophysics, CAS
2012/11/18 Taibei
OUTLINE
1- Promoting of the CGS mission
2- A brief introduction to the
Constellation
3- Open discussion about the science
object of the CGS mission
Grenoble Workshop about CGS On April 11, 2011
To Promoting the CGS Mission
In 2012, China Spacesat Co. Ltd. to design the CGS
It is confirmed that the Chinese companies have ability to product the small satellites and suitable rockets for the CGS mission.
Why are Chinese interested Why are Chinese interested
inin
geomagnetic satellite geomagnetic satellite
missions?missions?
It is related to Chinese history.
Needham has shown that the credit for the discovery of declination must go to the Chinese. Needham has tabulated eighteen recorded Chinese compass observations of declination covering the period about 720-1829. These are of interest not only to historians but also to geophysicists, for they represent the earliest recorded direct observations of the Earth's magnetic field. The question of their validity is therefore of great importance.
Magnetic Declination in China
CGS
Compass
MagNet
MagsatØrstedCHAMP
Swarm
Petrus Peregrinus (1269)Epistola de Magnete
CONSTELLATION• One satellite is in an orbit close to the equatorial plane One satellite is in an orbit close to the equatorial plane
• Four satellites are in polar orbits separated by 45° Four satellites are in polar orbits separated by 45°
Mass: 115 kg
Inclination: 87.4°
Altitude: 450 km
Pre. rate: -0.34 °/day
Spacecraft System Spacecraft System ArchitectureArchitecture
Spacecraft
Payload
Platform
Advanced Stellar Compass
Power Supply Subsystem
Attitude and Orbit Control Subsystem
Structure and Mechanism Subsystem
On-board Data Handing Subsystem
Thermal Control Subsystem
Communication Subsystem
d
Absolute Scalar Magnetometer
Fluxgate Magnetometers
Combined GPS, GLONASS,Galileo and Beidou
Occultation technique
Component Objectives
Core
Contribute to the long phase of synoptic monitoring of the core fieldMonitor flows in the core and their time changesInvestigate the interplay between velocity and magnetic fields
Mantle Perform 3D tomography of mantle conductivity
Crust Construct the lithospheric magnetic Construct the lithospheric magnetic map map
Environment Investigate the time-space structure of the magnetospheric and ionospheric sources on all time scales
CGS Scientific Objectives
(Dominique and Jackson, 2010)
1. Core Field
Dynamics of the Earth’s core, as estimated from the evolution of the magnetic field, evolves on a variety of timescales.
核幔界面外核
2. Monitor of Magnetosphere-Ionosphere Current System
AtmosphereIonosphere
GPSCGS
3. Atmosphere and ionosphere occultation technique
4. Crust Field Deep Structure of the Earth and Concentration of Metals in Lithosphere
古古亚洲成矿域亚洲成矿域
环太平洋成矿域
环太平洋成矿域
喜马拉雅喜马拉雅 -- 特提斯成矿域
特提斯成矿域
Considerations of the
constellation concept are for:
Good coverage in spatial, local time and seasons.
Separating of the core field, crust field, induced field.
Equatorial satellite is for monitoring the daily variations and equatorial current system.
80% data for single satellite were lost
Kp < 2; LT ~ 21:00 - 03:00
Equatorial satellite monitoring mid-low
latitude currents by the assimilation method
• Ring current: Storm-time geomagnetic
disturbance
• Sq current: ionospheric dynamo
• Eqatorial ElectroJet (EEJ): cowling current
• Cross tail current: Substorm current
• Magnetopause current: Solar wind ram
pressure
LONGITUDINAL PROFILE OF Bj FROM MAGNETOSPHERIC CURRENTS
Local Time0012 18 06 12
Dst
B
oo
o
o
j
N
j j
jst B
H
ND
1 cos
1
(Le Guan et al., AG, 2004)
EQUATOR CURRENT SYSTEM has a good longitudinal profile
Sq
C-F current Cross Tail current
DEDUCE THE ELECTRIC POTENTIALIN POLAR REGION
THEN MAPPING TO THE MID-LOW LATITUDE MAGNETOSPHERE
Geomagnetic IndicesGlobal profile in X componenton the ground
Magnetospheric Current System
Ring Current Auroral electrojet and Field-Aligned Current
FOR EXAMPLE
SUMMARY
The constellation constellation with one The constellation constellation with one near-equatorial orbit satellite and four near-equatorial orbit satellite and four polar orbit satellites should contribute to:polar orbit satellites should contribute to:
Separating of outer source field (noise) from the satellite data.
Modeling the magnetosphere-ionosphere current system (signal).
Discovering the small scale and short term variation of core field.
Constructing of mantle conductivity and lithosphere.
Thanks!
top related