Measurement of Auroral Electric Fields with an Antarctic Sounding Rocket S-310JA-7. 2.AC Electric Field

A sounding rocket with double-probes for DC electric field and AC electric field (5-220Hz band) measurement was launched from Syowa Station in Antarctica around the onset time of an intense auroral substorm. The rocket first encountered a poleward expanding auroral arc, where intense (1.4mV/m) and broad band electric field fluctuations were measured around the arc at the altitude of 105-128km. The rocket then moved across an equatorward drifting arc, where narrow-band electric field fluctuations around 40Hz were measured at the altitude of ∿190km. Considering the DC electric field data and the electron density gradient observed on the same rocket, it is likely that the former fluctuation is due to drift waves or ion acoustic waves excited by the cross-field type or two-stream type plasma instability, while the latter is due to electrostatic ion cyclotron waves excited by fieldaligned currents

High latitude aurora observed at Godhavn

On the basis of ground observations at Godhavn (77°INV) during the period from September 1988 to March 1989,we studied the characteristics of auroras on the higher latitude side of the aurora oval. Four typical kinds of auroras are seen in this region during this period. They are (a) bright poleward expansion auroras, (b) transpolar auroras, (c) sun-aligned arcs, and (d) morning side bright auroras. The intensity of (a), (b) and (d) auroras are very strong and these auroras are similar to those observed along the auroral oval. The sun-aligned arcs (c) are the typical aurora seen only on the high latitude side of the auroral oval. The relationships between these auroral features and other related phenomena are also discussed

Synthetic Observations of High-Latitude Ionosphere by S-310JA-4 Sounding Rocket

A comprehensively instrumented S-310JA-4 sounding rocket was launched into a ray band type auroral region from Syowa Station in Antarctica at 0032 (UT) on August 18,1978,in order to study mechanisms of high-latitude ionospheric disturbances, specifically to clarify the mechanism of ionospheric irreguralities in the aurora such as two-stream, cross-field and ion cyclotron instabilities. Payload instrumentations and ground-based observations corresponding to the mission objectives are discussed. All payloads functioned successfully and a general view of obtained data is also briefly outlined

The Results of Auroral Sounding with S-310JA-4 Rocket: Electric Field, Particle and Waves

The 310JA-4 rocket was launched perpendicular to the geomagnetic field line in the poleward direction from Syowa Station, Antarctica around the onset time of a small substorm (∿-140nT). The rocket moved across aurora of the ray-band type. DC electric field, plasma waves in a frequency range from 20Hz to 8kHz, auroral energetic electron (>90eV), electron density, and electron temperature were measured by onboard instruments. The measured electric field directed generally northeastward, the fact being interpreted as a modification of a large scale electric field (directing northward (equatorward) in the morning sector of the auroral region) by an eastward polarization electric field in the precipitation region. Auroral energetic electron flux up to 8×(10)^8 electrons/(cm)^2・s and auroral hiss were observed during the flight, and they showed a close correlation

Time-sharing measurements of ionospheric electron temperature and electron density with the electric field using double probes: An experiment on the Antarctic sounding rocket S-310JA-7

An experiment was carried out of a time-sharing measurement of auroral ionospheric electric field, electron temperature and electron density with double probes on board the Antarctic sounding roket S-310JA-7 on March 27,1978 at Syowa Station. The measurements of each element are compared with each other, and the electron temperature and density are compared with the other independent measurements which were made simultaneously on board the same rocket. The principle of the measurement of electron temperature and density with double probes is described in detail in the Appendix