RADIO SCINTILLATION OBSERVATIONS OF THE SOLAR WIND - RECENT RESULTS FROM EISCAT AND PROPOSALS FOR A NEW-GENERATION SYSTEM A.R. Breen(1), G. Woan(2) (1)University of Wales Aberystwyth, Ceredigion SY23 3BZ, Wales, Email:
[email protected] (2)University of Glasgow, Glasgow G12 8QQ, Scotland, Email:
[email protected] ABSTRACT the spectral shape measured by a single antenna [2, 3] Measurements of radio scintillation which use the or – with greater accuracy, from the form of the cross- motion of ~100 km scale size density irregularities as spectra of the scintillation patterns measured at two flow tracers for solar wind speed (the technique of widely-separated sites at a time when the raypaths from Interplanetary Scintillation or IPS) have been used to source to antennas lie in a plane radial to the Sun [4, 5]. study the solar wind for many years. Recently Single antenna systems can make many more improvements to analysis methods have transformed observations but velocities derived from multi-site the capabilities of this technique and it has emerged as systems allow more accurate estimates of velocity [6]. a powerful tool for probing regions of the solar wind IPS measurements contain contributions from the which are hard to study by other means - particularly whole of the extended ray-path through the solar the region from ~25 solar radii (R) out to ~100 R. As atmosphere from the distant source to the receiving this is the region in which interaction between streams antenna(s). In earlier studies the inability to distinguish of solar wind and between mass ejections and the between contributions from different regions of the background wind determine the solar wind structure solar wind led to a "blurred" view of solar wind seen at Earth orbit good measurements of this region structure.