Several plasma wave emissions observed by GEOTAIL, POLAR, and WIND are related to substorms. Comparison of the wave characteristics between the three ISTP spacecraft as well as to other space and ground substorm observations allows us to study both the sources of the waves and the plasma dynamics. AKR has long been known to be related to geomagnetic activity. Observations from multiple spacecraft aid us in separating differences in the AKR spectra due to generation or propagation effects.
Low frequency (LF) bursts are a part of AKR observed during strong isolated substorms detected by the CANOPUS and other magnetometer networks. We have found that more high frequency AKR is detected by either GEOTAIL or WIND during LF burst events only if the path from the AKR source is not blocked by the earth or dense plasmasphere.
POLAR observations from high over the AKR source region show that the AKR increases in intensity and its lower frequency limits when LF bursts are observed indicating that the AKR source region is expanding to higher altitudes. Frequently the upper frequency limit also increases indicating that the source region is then also expanding to lower altitudes.
Images from the POLAR VIS Earth Camera operating in the far-UV range usually feature a strong enhancement in the aurora at the time of the LF bursts.
CANOPUS ground magnetometer and meridian scanning photometer data show that during the LF burst events the expansive phase onset starts at unusually low latitudes and moves poleward. The data also show that the LF bursts occur when the expansive phase onset signatures are most intense.
Many of the LF bursts occurred related to CME events observed by SOHO which were later identified by the NOAA SEC as being highly geoeffective.
Magnetometer data from geosynchronous satellites usually show increased magnetic field dipolarization and the presence of field-aligned currents during LF burst events. Large injections of protons and electrons have also been detected by the GOES and LANL geosynchronous satellites during LF burst events. For one event a sudden injection of energetic electrons was detected by the LANL 1991-080 satellite near dusk simultaneous with POLAR VIS observations of auroral brightening near the magnetic footprint of the LANL satellite.
Plasma wave observations from GEOTAIL, POLAR, and WIND of continuum storms and enhanced escaping continuum radiation produced by injected plasma drifting around the magnetosphere and impinging on the plasmasphere also help describe plasma motion during substorms. Recently we have found an event where an abrupt and isolated increase in AKR detected by POLAR as it passed through the source region precedes the detection of precipitating electrons by many tens of seconds.
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