About the Culgoora Solar Radio Spectrograph Type II Tool Display

The display consists of the current real time Learmonth Spectrograph image with a row of three buttons at the top of the image, "clear", "compute speed" and "fundamental".

Selecting shock type:

The shock type can be selected by clicking on the button labeled "fundamental" (default) located at the top of the display. A two item drop down menu appears, and shock type (fundamanetal or harmonic) can be selected by using the left mouse button. The shock type should be selected before inputing the shock points.

Inputing shock points:

To input shock points for speed computation click along the shock in the image at several points from top left to bottom right. Each point clicked is marked by the frequency (F) at that point and the number of seconds (S) from the first point clicked. The "Newkirk" model used for conversion from frequency to altitude in the solar atmosphere has a upper frequency limit of 540MHz if harmonic is chosen and a limit of 280MHz if fundamental is chosen. Points clicked above these limits will not be displayed.

Computing shock speed:

To compute shock speed click on the button labeled "compute speed". The result is displayed top right of the image.

Clearing input:

The "clear" button clears all input data.

Also, when using this tool it is important to note that there are no time discontinuities in the data image.

Why is it done?

Type II radio burst shock speeds can give an indication of the travel time of a coronal mass ejection from the Sun to the Earth. You can view some example events from the drop down list, and also select hourly images for the current day.