Some NIfty WAVES Data


A portion of the WAVES instrument is devoted to radio astronomy. Emissions are detected from a variety of naturally occurring radio sources such as the sun, the earth's auroral zones, and Jupiter. The solar bursts shown at the right were also detected simultaneously by the Ulysses URAP experiment (same team as WAVES). Ulysses was at high solar latitude and some 2 AU away at the time. Triangulation of solar bursts by WAVES and URAP will permit remote determination of the plasma density and magnetic field topology from the sun to the earth. The very lowest frequencies in this display show emission from the in situ solar wind plasma. WAVES can determine the density of this plasma with very high time resolution (<1 sec).


A portion of the WIND/WAVES instrument covers a frequency band from 1 to 14 MHz that has been long ignored. It is in this region of that radio spectrum that solar emission originating very close to the sun can be studied. However, the most dominant radio source in this part of the spectrum is man-made emissions in the short wave radio band. Here is a fairly typical day of WAVES data displayed as frequency-time spectrograms with color-coded intensity. The bright horizontal bands of noise correspond the allocated short wave broadcast bands as shown at the right. These are the bands in which the BBC, radio Moscow and all the other national radio stations broadcast. At the top are views of the earth from WIND at selected times. During the early part of the day when the emissions are most intense, the middle East, the Indian sub-continent, part of Africa, and south-east Asia are visible. North and South America are visible during the middle of the day and Japan, China and Australia toward the end of the day. Both the FCC and the U.S. Air Force have expressed considerable interest in WAVES' ability to monitor the man- made emissions and we will be working closely with them.


Author -- Michael L. Kaiser ( March, 1995