ROCKET OBSERVATION OF EQUATORIAL PLASMA BUBBLES OVER NATAL, BRAZIL: EVIDENCE OF ELECTRON TEMPERA TURE ENHANCEMENT INSIDE BUBBLE

In situ measurement of electron density height profile of the equatorial nighttime ionosphere, under a developing spread F event was carried out using a dual mode High Frequency Capacitance (HFC) probe that was flown onboard a SONDA-3 rocket launched from Natal on 11 December 1985. A series of plasma bubbbles in varying degrees of their growth phase was detected by the HFC probe mostly during the upleg of the flight. A somewhat detailed discussion, and comparative studies, of the measurements at the two frequencies (6.2 MHz and 11.7 MHz) are presented in this paper. Among the important findings from the present study is an evidence on electron temperature enhancement in the plasma bubble possibly caused by electron heating from energetic particle precipitation in the South Atlantic Magnetic Anomaly.