Phase scintillation observation during coronal sounding experiments with NOZOMI spacecraft

Abstract

Radio occultation observations of the solar corona at solar offset distances of 12.8-36.9 RS were performed from December of 2000 to January of 2001, using the Nozomi spacecraft (Planet-B) of Japan. Phase scintillation spectra up to the frequency of ∼10 Hz were obtained in two-way mode with S-band uplink and X-band downlink. The spectra cannot be represented by a single power law especially for small offset distances. That is, at low frequencies (large scales) the spectra show slopes indicative of Kolmogorov, a local flattening occurs from ∼0.5 Hz (scale ∼600 km) to ∼3 Hz (∼100 km), and a steepening occurs again at higher frequencies. This three-component nature of the spectrum was observed with a single method for the first time, although the spectral shape is variable and the three-component feature is not always evident. © ESO 2005.