Electron Fluence Levels Help


The daily MeV electron fluence can be used to estimate the risk of internal charging anomalies using a threshold level. If the fluence is below the threshold level the risk of anomaly is small and if the fluence is above the threshold level the risk is high.

Based on the dates from an anomaly list the >0.6 MeV and >2 MeV GOES-8 electron fluence are calculated. The threshold levels for the two energies that best match the anomaly data are then found. It is also examined whether there is a time delay between the fluence and the anomaly.

To carry out the analysis do the following:

  1. Enter the events by pushing the "Edit Events ..." button.
  2. Enter the non-events by pushing the "Edit Non-Events ..." button.
  3. Push "Optimize ...".

The two windows will now display the result for the 0.6 MeV and 2 MeV energy levels. The optimization procedure carries out a search by varying the time delay and the threshold level. The optimal model is the model that gives the highest probability of correct predictions.

The time delay is varied from -5 days to +5 days in one day steps. A time delay of -5 days means that there is a five day forecast possibility from the electron fluence.

The >0.6 MeV threshold level is varied from 107 to 1011 cm-2 sr-1, and the >2 MeV threshold from 105 to 109 cm-2 sr-1.

Other values of time delays and threshold levels can be entered. Then, pushing the "Run" button will use these new values and the calculated probabilities will be displayed.


Peter Wintoft, Wednesday, August 29, 2001