Ionospheric Irregularities

摘要

Ionospheric irregularities cause scintillations of trans-ionospheric radio waves from satellites. Most severe cases are the scintillations due to plasma bubbles at low latitudes near the magnetic equator, which results in fluctuations of L-band radio signals by 20 dB or more. For the prediction of onsets of plasma bubbles, investigation of a physical mechanism is indispensable. Also precursory phenomena of bubble onsets will be valid for the prediction. This article describes outstanding problems for the prediction of severe ionospheric scintillations and an ongoing observational approach in CRL.