SPP
Space Plasma Physics Group
Education and Outreach

Radiation Belts: The Big Picture

•The Radiation Belt is a energetic torus of energetic charged particles (plasma) around Earth, held in place by Earth's magnetic field
• Historic discovery in 1958 by the Explorer I in 1958, and Explorer III missions, under Dr.James Van Allen at the University of Iowa.
• The trapped radiation was first mapped out by Sputnik 3, Explorer IV, Pioneer III and Luna 1.
• Energetic electrons form two distinct radiation belts, while protons form a single belt.
The Radiation Belts Today: a Dynamic Space Weather Environment

Space Weather Applications:

• Astronauts  safety
• Hardware integrity
• Mission performance 
• Satellite solar cell panel degradation 
• Single Event Upset (SEU)
Video and Multimedia
Substorm and storm dynamics of Earth’s magnetosphere. A movie example is developed for Apr. 22, 2002 storm event and provides a global view of complex dynamical behavior of the Earth’s magnetosphere and ionosphere. The semi-transparent grey mantle is the 3D envelope of the last-closed Earth’s magnetic field lines. Plasma flows are shown in black arrows and the density of the plasma is also shown in colors that denote large (red) and small (blue) values. Contours in the black circle show evolutions of electric field inside Earth’s ionosphere (~100 km above Earth’s surface).
Vortices structure and Ring Current development inside the magnetosphere during Mar. 29, 2002 magnetic storm events. Bottom panel shows evolution of the solar wind conditions. Upper left channel shows the plasma velocity vectors overlaid on top of the colormap of the velocity amplitude. The two panels on the right show the evolution of ring current particles (protons) in two energy channels. In responding the solar wind’s perturbations, vortices structure and ring current are developed and showing dynamic behavior inside the earth’s magnetosphere.
When Earth's magnetic field is disturbed by a solar storm event, many changes occur which lead to complex rearrangements of earth's magnetosphere, and the particles that flow within it. This animation was calculated for one such 'magnetospheric substorm' to show the complexity of these rearrangements. The lines are a few of the magnetic field lines from earth. The density of the trapped plasma (charged particles) is also shown in colors that denote large and small values.
As the magnetic field of Earth undergoes a storm, trapped particles flow in specific ways as magnetic fields compress and energize them. This computer model animates how protons (the nuclei of hydrogen atoms) flow within a radiation belt during a magnetic substorm. The lines are the magnetic field lines of earth, and the balls represent a few of the trillions of protons which are flowing in the various belts and currents. The colors represent the different energies carried by the protons. It can be noticed that energetic protons circle around the earth clockwisely.
At the same time the protons are flowing around Earth and being energized by magnetic forces, electrons are also flowing in similar regions of space. This computer model shows many similarities and differences between the electron belts and the proton belts. As before, The colors represent the various energies of the electrons while the lines represent the calculated locations of Earth's magnetic field. It can be noticed that energetic electrons circle around the earth counter-clockwisely.
Presentations
Earth's Radiation Belt
by: Dr. Xi Shao
This Presentation is about Earth's radiation belt observations, geomagnetic storms and sub storms, modeling formation of Earth's radiation belt, and slot region formation. The target audience is the general public
Interactive Radiation Belt Database
Magnetospheric State Query System
by: Dr. Xi Shao
An interactive Magnetospheric State Query System (MSQS) is developed and maintained by Dr. Shing F. Fung and Xi Shaoand hosted at http://radbelts.gsfc.nasa.gov/RB_model_int/Psi_database.html. From this web page, the user can select time intervals when a set of user-specified geophysical conditions occurred. Time intervals from MSQS can be used directly to select, retrieve, and analyze the observations associated with a given magnetospheric state [Fung and Shao, 2007].
Radiation Belt Database:

NOAA POES satellite data covering 20 years continuous o5tbservations of Earth’s radiation belt particles (protons and electrons) have been processed and make available to the public through CDAWeb of NASA. Currently, it is available at http://cdaweb.gsfc.nasa.gov/sp_test/ (select NOAA). This radiation belt database will be officially released in September, 2007 along with the documentation by Tan et al., [2007]. Part of Xi Shao’s work on this data product is supported through NASA Grant.

Useful Links:
Nasa Radiation Belt Modelijng for Living with a Star http://radbelts.gstc.nasa.gov
The Development of this educational web page is supported by NASA Grant -05-NIP
Award # NNX06AE88g, (PI: Dr. Xi Shao)
Questions and Comments sent to Dr. Xi Shao (xshcn@astro.umd.edu)
References:

  1. Collado-Vega, Y., Kessel, R., Shao, X., Boller, R. MHD flow visualization of magnetopause boundary region vortices observed during high speed streams. Journal of Geophysical Research, VOL. 112, A06213, doi:10.1029/2006JA012104, 2007.

  2. Vassiliadis, D., I.R. Mann, S.F. Fung, X. Shao, Ground Pc3–Pc5 wave power distribution and response to solar wind velocity time variations. Planetary and Space Science, doi:10.1016/j.pss.2006.03.012, Volume 55, Issue 6, 743-754, 2007.

  3. Chen, J., A. S. Sharma, and X. Shao, Spatio-temporal dynamics of substorms during intense geospace storms, Proceedings of the 8th International Conference on Substorms, edited by Syrjäsuo and Donovan, University of Calgary, Alberta, Canada, 31-36, 2007.

  4. Fung, Shing F., and X. Shao, Specification of Multiple Geomagnetic Responses to Variable Solar Wind and IMF Input, submitted to Annales Geophysicae, 2007.

  5. Lun C. Tan, Shing F. Fung, and Xi Shao,NOAA/POES MEPED Data Documentation: NOAA-5 to NOAA-14 Data Reprocessed at GSFC/SPDF, NASA, Space Physics Data Facility, 2007. (To be released in September, 2007 along with NOAA Radiation Belt Particle Data).