Wave electric field measurements in a dusty plasma in the polar summer mesosphere gathered on a NASA sounding rocket

Summary form only given. Launched in July, 1999 from Andoya, Norway, a NASA sounding rocket, 21.123, included probes to measure the vector DC and AC electric fields in a polar summer mesosphere "dusty plasma" near 85 km altitude. The instruments included 3.0 m tip-to-tip double probes in two orthogonal spin plane directions as well as along the payload axis. Additional inboard sensors provided diagnostics and wave interferometry. The response of the double probe within the polar summer mesosphere dusty plasma is not straightforward to interpret. For example, the double probe data strongly suggest that the charged particle environment undergoes significant variations within the narrow layer, creating DC electric fields in the vicinity of the conducting payload that may or may not be of geophysical origin. On the other hand, the AC electric field measurements reveal distinct, structured layers of intense fluctuations that appear to be geophysical and almost certainly pertain to the simultaneously measured VHF backscatter radar echoes that originate in this region. The wave amplitudes were as large as 10 mV/m with rocket-frame frequencies greater than 4000 Hz, corresponding to scale sizes of tens of cm or smaller. The waves were observed both within and around abrupt depletions of the electron density measured with a Langmuir probe on the same payload. The correspondence of the wave electric fields to these depletions, as well as to the heavier charged particle distributions, will be discussed.