APPLICATION OF ALTERNATING CODES FOR EISCAT OBSERVATIONS DURING THE ERRRIS CAMPAIGN FOR E-REGION PLASMA IRREGULARITIES

The first extensive use of alternating codes in incoherent scatter experiments took place during the ERRRIS campaign in March and April 1988. Alternating codes provide a very powerful technique which in theory offers time resolution a factor of 5 shorter than is possible with the commonly used multipulse codes for low signal-to-noise ratios. For quiet conditions during the ERRRIS campaign this was confirmed by the remarkable consistency of measured parameters which were adjacent in time or height, indicating a low level of random error even for integration times as short as 45 s. This gave confidence in the value of the parameters measured during disturbed periods when the electron temperature at 110km reached values of several thousand kelvin for short periods, with simultaneous increases in ion temperature at greater heights. © 1990.