Rocket Observation of Electron Density Irregularities in the Lower E Region
1990 年 42 巻 1 号 p. 19-33
詳細
1990 年 42 巻 1 号 p. 19-33
Local ionospheric electron density irregularities in the scale size of 3m to 300m have been measured on the ascending path from 74km to 93km by a fix biased Langmuir probe on board the S-310-16 sounding rocket. The rocket was launched at 22:40:00 on February 1, 1986 from Kagoshima Space Center in Japan. It is found from frequency analysis of the data that the spectral index of the irregularities is 0.9 to 1.8 and the irregularity amplitude is 1 to 15%. The altitude where the amplitude reaches its maximum is 88km.
The generation mechanism of these irregularities is explained by the neutral turbulence theory, which indicates that the spectral index is 5/3 and has been confirmed by a chemical release experiment using rockets over India to be valid up to about 110km.
From frequency analysis of the data observed during the descent in the lower E region, we have found that the rocket-wake effect becomes larger when the probe is situated near the edge of the rocket-wake, and that this is also the case even when the rocket-wake effect does not clearly appear in the DC current signal which approximately changes in proportion to the electron density, where the probe is completely situated inside the rocket-wake region.
