Cusp particle detection and ion injection source oscillations
Frahm, Rudy Allan
Reiff, Patricia H.
Master of Science
The magnetic merging process has been suggested as a means for particle injection into the cusp regions of the earth's magnetosphere. If this process occurs, the injected plasma should reveal a characteristic signature. Electrostatic analyzers are used to detect this plasma. This thesis discusses the design of the electrostatic analyzers which are the central components of the High Altitude Plasma Instrument (HAPI) and Low Altitude Plasma Instrument (LAPI) flown on DE-A and DEHB (Dynamics Explorer satellites) respectively. Also discussed is the calibration of the electrostatic analyzers which I was involved in. This includes the co-authored calibration data acquisition program and my Calibration Data Reduction Routine. Typical satellite instrument output is in spectrogram energy-time format with the particle flux intensity indicated by gray shading. This presentation gives a "visual picture" of how the differential energy flux at each energy changes with time. A presentation of this type using the DE-A HAPI data shows the magnetic merging injection signature: multiple ion "V" structures as the satellite passes through the cusp region when the interplanetary magnetic field has a southward component. An alternative output format which I have helped create produces individual line spectra which allows these "V" structures to be examined in finer detail. If one looks at these "V" structure spectrograms, it is easily noticed that they appear to pulsate with time. I have conducted a harmonic analysis of the peak distribution function per spin from several satellite passes- to determine the periodicity of these pulsations, perhaps related to Kelvin-Helmholtz waves at the magnetopause.