The First Solar-Terrestrial Research Campaign of

the Inter-Agency Consultative Group (IACG)

Background of IACG

The Inter-Agency Consultative Group for Space Science (IACG) was formed in 1981 by the science administrators of four major space agencies: the European Space Agency (ESA), Intercosmos of the former USSR which is now the Russian Space Agency (RSA), the Institute of Space and Astronautical Science (ISAS) of Japan, and the National Aeronautics and Space Administration (NASA). The purpose of the IACG is to increase the overall science return from their missions through cooperation. The IACG has a World-Wide-Web site for information about its activities and the status of the scientific campaigns it is supporting. The IACG's first project was to coordinate the Agency's space-based missions to the Comet Halley (Reinager, 1986) . Several years before Comet Halley made its close encounter with the Sun in the winter of 1985, a total of six spacecraft from ESA, Intercosmos, and ISAS were launched to make individual observations of the comet. Realizing that many aspects of Halley Comet science observations be improved through cooperation, the IACG undertook the task of coordinating all matters related to the space missions to Halley s Comet and the observations of the comet from space. Together, these six spacecraft were able to accomplish unprecedented coordinated science during the comet flybys of March 6 to March 14, 1986, as a result of this cooperation. The success of the Comet Halley activities led each agency to recognize the value of maintaining close international collaborations. The IACG next turned its attention to conducting coordinated Solar-Terrestrial research.

Since its formation, the IACG has met annually wit h meetings chaired by the recognized science head from the hosting agency. Much of the work is carried out in three working groups and three panels, usually in combination with another major meeting or just prior to an IACG meeting. The three IACG working groups address all aspects of accomplishing enhanced science coordination. Specifically, Working Group - 1 (WG-1) is the science working group and is chaired by Dr. Arnie Pedersen of ESA. WG-1 makes recommendations on the potential science coordination, including:

• definition of science objectives which can only be achieved by multiple agency missions
• identification of data requiring coordinated acquisition
• ensuring compatibility of scientific measurements
• identification and specification of appropriate solar-terrestrial models
• formulation of data exchange policies and rules
• sponsorship of scientific workshops and symposia for the wider scientific community

The IACG Working Group -2 is involved in supporting WG-1 through coordinating data exchange issues between the agencies. This group is presently chaired by Dr. James Green of NASA. WG-2 makes recommendations on data exchange issues, such as:

• specifying the capabilities of the computer networks between the agencies
• technical aspects of implementing information and data exchange formats
• facilitating the science campaigns

• Working Group-3 (WG-3) is the Mission Design and Planning Working Group and is chaired by Tono Uesugi of ISAS. This working group supports Working Group-1 on operations aspects of the multi-mission coordination, supported by satellite operation facilities from each agency. Besides the working groups, three panels currently are actively discussing future cooperative research.
  
• The IACG Campaigns
• To accomplish its goals of enhancing the scientific return from its space science missions the IACG has chosen a well defined set of coordinated campaigns, each of which have specific questions to answer in understanding the solar-terrestrial environment that extend well beyond the individual mission science objectives. Presently, there has been four campaigns defined. The campaigns are:
  
  • 1st: Magnetotail Energy Flow and Non-linear Dynamics
  • 2nd: Boundaries in Collisionless Plasmas
  • 3rd: Solar Events and Their Manifestation in Interplanetary Space and in Geospace
  • 4th: Solar Sources of Heliospheric Structure Observed out of the Ecliptic
• An Overview of the 1st Campaign

• The Airlie House Workshop on Magnetotail Energy Flow and Non-Linear Dynamics held at Airlie House, Virginia, June 1-3, 1992, defined two overarching science research themes, and a two-phase campaign plan focusing on: (1) The Structure of the Global Magnetotail System, especially during quiet periods; and (2) Magnetotail Effects of the Global Solar Wind--Magnetosphere Interaction, especially during active periods. The scientific objectives of the 1st Campaign are discussed in detail in the Airlie House Workshop report edited by Whipple and Lancaster, 1992.
  The prime objective of the first campaign phase is to use the widely-spaced IACG satellites along with ground-based data, other spacecraft, and modeling tools to gain an understanding of the large-scale configuration of the magnetotail system. The specific science questions to be addressed in this campaign phase are:
  
  1. Boundary Region Structures:
     
     • How does the thickness of the LLBL and HLBL vary with upstream solar wind conditions (e. g., IMF orientation and strength)?
     • How does the fine structure of the LLBL vary with upstream solar wind conditions; do solar wind inhomogeneities penetrate into the boundary layers?
     • What is the evidence for reconnection along the flanks of the magnetopause; how does the process vary as a function of upstream conditions (IMF orientation, plasma beta, mach number)?
     • Where is the magnetopause locally open and closed; how does openness vary with upstream field orientation, distance down the tail, and time?
     • How do the large-scale vortices in the tail vary with solar-wind speed and IMF strength and orientation; what is the evidence that they are driven by a Kelvin-Helmholtz instability?
     • Does the plasma sheet bifurcate, or form fingers, when the IMF turns northward?
     • How much of the solar wind electron heat flux enters into the tail lobes; how is this entry regulated by the IMF?
  2. Quiescent Configurations
     
     • Does the magnetosphere have a ground state during quiet conditions?
     • What is the structure of the quiet-time magnetosphere?
     • What are the sources of the magnetotail plasma?
     • How does the high-latitude ionosphere respond to magnetospheric activity in quiet conditions?
     • How do MHD waves transfer energy under quiet conditions?
  3. Origin of Plasma in the Plasma Sheet
     
     • What are the relative source strengths of the solar wind and the ionosphere?
     • What are the underlying plasma-physics mechanisms, including convection, heating, and acceleration, that are responsible for the transport of plasma from these source regions into the plasma sheet?
• The second phase of this campaign deals with the storage and release of energy within the magnetotail, especially during both sub-storm and storm conditions, and with the many macroscale manifestations of these energy transfer processes in the near-Earth and distant-tail regions. The IACG suite of spacecraft is ideally suited for such studies. The goal of the second campaign phase is to answer the following specific set of science questions including:
  

1. Dynamic Magnetotail Configuration
   
   • How do the magnetotail orientation and configuration depend on solar wind plasma properties such as the upstream density, velocity and pressure?
   • How do the magnetotail orientation and configuration, including twisting and oblateness, depend on the interplanetary magnetic field (IMF)?
   • How does the magnetotail configuration map into the ionosphere; in particular, how do the open tail lobes map to the polar cap and relate to its size and location?
2. Externally Driven Disturbances
   • How quickly can the magnetosphere accommodate itself to new external conditions, such as changes in the solar wind pressure, changes in the solar wind flow direction, different polarities of IMF, etc. (Dynamical response of the magnetospheric convection to changes in the direction of the IMF, for example, give s us a clue to finding where a specific mode of magnetospheric convection is initiated and how the convective motion expands throughout the magnetosphere).
   • How is deformation of the magnetosphere induced by sudden changes in the solar wind pressure propagated to affect the internal state of the magnetosphere? Such changes in the internal state may trigger instabilities that may lead to substorms.
     
   • Does a feature in the upstream solar wind produce a coherent response throughout the entire magnetosphere, or is there a response only on the dayside, or in a portion of the tail, etc.?
3. Internal Magnetospheric Instabilities
   
   • What are the key processes in substorms?
   • Where is the substorm trigger region?
   • What disrupts magnetospheric currents during substorms, and how are they reconfigured?
     

• For the 1st Campaign, the IACG core missions are Geotail (ISAS), Wind (NASA), Interball-Tail (a spacecraft pair from RSA), Interball-Auroral (a spacecraft pair also from RSA), and the Polar (NASA) spacecraft. At this time only Geotail, Wind, and Interball-Tail are in orbit. However, many of the scientific objectives defined in the Airlie House report can now be tackled and it has been decided to move the campaign forward. Ancillary data are also being used in the 1st Campaign and include selected instruments on (but are not limited to) IMP-8, GOES 6 & 7, the Los Alamos National Laboratory equatorial spacecraft, and a variety of ground based radar and other instruments. For the operational core missions Table 1 lists all the instruments and Principal Investigators for the 1st Campaign.
  
• Campaign Implementation

• To facilitate the execution of the first campaign, a Coordination Committee consisting of A. Nishida (ISAS), M. Acuna (NASA), R. Schmidt (ESA), L. Zelenyi (IKI) and the Lead Coordinator, J. L. Green (NASA) has been formed. The responsibility of the Coordination Committee is to represent the individual project teams within their agency and to insure that as many of the scientific objectives (as outlined above) as possible are addressed by the campaign.
  Nearly all spacecraft and ground-base projects operate under a set of data exchange rules that identify obligations of researchers about data provided by other science research investigators. Because the scientific aim of the IACG 1st Campaign is, by design, multi-mission collaborative efforts, which greatly extends this interchange of data within the international research community, a set of "Rules of the Road" have been adopted for use in the IACG 1st Campaign. The rules provide information on how interested researchers can become campaign members.
  It has been decided that the WWW will be used to provide rapid access to the Campaign data and information.
• Event Intervals
  

At the Working Group 1 meeting in Sapporo, Japan on September 6, 1995 the Campaign 1 event times were selected. These intervals were based on having a solar wind monitor (Wind or IMP-8) with Geotail and Interball-Tail near their apogees in the mid-tail regions. The intervals are given in the following table.

Day of the year                   Date  
    293-294                October 20 -21, 1995 
    299-300                October 26-27, 1995 
    304-305                October 31 - November 1, 1995 
    315-316                November 11-12, 1995 
    321                    November 17, 1995 
    331-333                November 28-29, 1995 
    337-338                December 3-4, 1995 
    341                    December 7, 1995 
    349                    December 15, 1995 
    352-354                December 18-20, 1995 
    12                     January 12, 1996 

• The Chapman Conference on The Earth's Magnetotail: A New Perspective is being planned for late 1996 in Japan and will be co-sponsored by the IACG to support the presentation of the scientific results from the analysis of the acquired data during the above campaign intervals.
  
• References
  Reinhart, R., The Inter-Agency Consultative Group, ESA bulletin, 1986.
  
  Whipple, E., and H. Lancaster, editors, Toward a New Era of Global Solar-Terrestrial Research: 1st IACG Campaign on Magnetotail Energy Flow and Non-linear Dynamics, SAIC, October 1992.
  
  

Return to IACG First Campaign Home page



Last Modified:
(G.C.G.)