IMP-8 EECA Page




The Electrostatic Energy-Charge Analyzer (EECA) is the University of Maryland experiment on the IMP-8 satellite. Online plots and data of selected rates from EECA are listed below. Each plot covers one orbit, and each is color-coded to show the nominal positions of the bow shock and the magnetopause. Data are available from the P3, P5, P7 and A2 detectors:


An example of how this data is used can be seen in an accompanying figure, which shows an increased flux of >20 MeV protons caused by a solar flare on 12 May 1997, followed 3 days later by an increase in the 200 keV protons. The latter are locally accelerated, and are associated with the passage of a shock that was probably related to the solar flare. Notice the decreased intensity of the >20 MeV protons after the shock passage. This depression, known as a "Forbush Decrease", represents a decrease in the intensity of galactic cosmic rays reaching the earth produced by strong magnetic fields in the post-shock region and in the succeeding solar material that is driving the shock. The solar wind behavior during the shock passage is shown in another figure, as measured by the Proton Monitor Instrument on the SoHO spacecraft.


NSSDC SPDF have 11-min EECA data in ASCII here.

For more information about EECA please contact Dr. F. M. Ipavich

For comments/questions on this web page please contact Scott Lasley

IMP8 Experimenters Meeting 1974
IMP8 Experimenters Meeting, 1974
Last Updated: 20 Feb 2007