RSC - Research Projects - Spacecraft Charging (DE)

Spacecraft Charging (DE)

Dynamics Explorer-1 had an instrument which could bias an external aperture plane.  The charging research here  basically redid an old Elden Whipple paper, but with the new instrument.  One of a number of papers I did for/with Rick Chappell in Huntsville.

Aperture Plane Potential Control for Thermal Plasma Measurements.  (copies of the 'original' spectrograms are on the Day 287 page).

This work includes the October 1981 data described below for the Polar Wind.  Everybody was pretty happy about how well the aperture bias worked, and on the basis of 20-minutes of data, we decided to use an 8-V negative bias for a large fraction of the measurements thereafter.  When the pitiful NASA data system finally gave us a significant amount of data (much, much later), we found to our horror that the channeltrons were being saturated, and we pretty much killed off the radial low-mass channel, the one that measured hydrogen (and gave pitch angle distributions).  This was at least partly due to the short in the RPA grids, which also eluded us for months.  

Multipole Model

One of the big things everybody wanted to see with DE-1 was the Polar Wind.  There was a fair amount of furor early on - Chris Gurgiolo used some of the HAPI electrostatic analyzer data (Jim Burch, SwRI), to stake a claim.  Meanwhile, in Huntsville, we had focused much of our attention on the aperture bias data set from day 287.  

Jan Sojka at Utah State did a paper with this data set, as well (Sojka et al, Characteristics of thermal and suprathermal ions associated with the dayside plasma trough as measured by the Dynamics Explorer retarding ion mass spectrometer, J. Geophys. Res., 88, 7895-7911, 1983.)    

From Huntsville, Tsgunobu Nagai did a GRL article, where I was a co-author:

First Measurements Of Supersonic Polar Wind In The Magnetosphere, GRL, pages 669-672, 1984

There is a longer technical report with many of the nitty-gritty details of the RIMS behavior, including an annoying feature involving channeltron saturation.  Charging Characteristics Of Dynamics Explorer 1.   There was also a conference publication version given at the ESA symposium. A Potential Control Method For Thermal Plasma Measurements on the DE-1 Spacecraft....



rco, 5/30/2017