Introducing the Solar Radio Program

The Solar Radio Monitoring Program is a service operated by the National Research Council and Natural Resources Canada with support from the Canadian Space Agency. Its function is to provide current and previous values of the 10.7cm Solar Flux solar activity index to any user to whom it might be of use.

The various manifestations of solar activity are driven by the total amount of magnetic flux emerging through the photosphere into the chromosphere and corona, and its temporal and spatial distribution. For reasons not clearly understood, solar activity ebbs and flows over a cycle of about 11 years. The 10.7cm Solar Flux is a measurement of the integrated emission at 10.7cm wavelength from all sources present on the disc. It is almost completely thermal in origin, and directly related to the total amount of plasma trapped in the magnetic fields overlying active regions. This in turn is related to the amount of magnetic flux. A comparison made over more than a solar activity cycle show that there is indeed a linear correlation between the 10.7cm Solar Flux and the total photospheric magnetic flux in active regions.

The 10.7cm Solar Flux, i.e., the solar flux density at 10.7cm wavelength is measured using two fully automated radio telescopes (called Flux Monitors), located at the Dominion Radio Astrophysical Observatory.

The two instruments record the strength of the solar radio emission at 10.7cm wavelength each day for as long as the Sun is above the horizon. In addition, the instruments interrupt the continuous monitoring each day to make three precise measurements of the solar flux density. These measurements constitute the 10.7cm Solar Flux index. These measurements are transmitted immediately by E-Mail and fax to a worldwide list of users. In addition current and past data are available on these Web pages, and can be downloaded.

Also available on the web are the daily records of receiver output, known as CR or Chart Record files. These comprise 5-second averages of the receiver output for each observing day. These records are occasionally interrupted by maintenance and system tests.