A determination of F region convective electric fields from rocket measurements of ionospheric thermal ion spectra

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Abstract
A detector package designed to measure the bulk flow of heavy ions was developed for sounding rocket studies of the lower ionosphere. The unit was first flown on board Electron Echo 3, which was launched eastward from Poker Flat Research Range on April 17, 1974. From least squares fits of a shifted, drifting Maxwellian distribution to direct measurements of the ionospheric particles' thermal energy spectra, average values of rocket payload potential, ion temperature, and bulk plasma flow were obtained. By interpreting the bulk flow velocity transverse to the local magnetic field as convective drift the strength of convective electric fields was inferred. Parameters determined from the data support an ion temperature of 1500 ± 94°K, a payload potential of 1.2 V, and convective field values of 6 ± 4 mV/m east and 25 ± 4 mV/m north. These values compare with an ion temperature of 1000°K, a northward field of 21 mV/m and an eastward field of O mV/m as measured by the auroral backscatter radar at Chatanika, Alaska. Results from the electron echo experiment are also consistent with these electric field values.