Generating event lists

On the SEPEM server, an event is defined as a time period during which a user selected parameter exceeds a user defined threshold. This broad definition encompasses the usual definition of SEP events based on an analysis of energetic proton flux time series, but also allows to generate more specific lists based on, for instance, radiation effect parameters such as Total Ionsing Dose (TID) or Single Event Upset (SEU) rates.

The SEPEM reference event list has been generated with the functionality provided on this page.

Data selection

The first step in the definition of an event list is to select a time series. First, select between data tables or response functions using the radio button. When no response functions have been defined yet for your account, the response function selection line will not be shown. Response functions which are not up to date cannot be selected.

Next, select a data table or response function from the respective selection lists. When a selection is made, the page reloads to display additional selection menu's for data channels or radiation effects.

Event parameters

When a data channel or radiation effect has been selected, the page reloads to display the event parameter menu. The value range at the top is shown to guide the user with the selection of threshold parameters.

Six parameters are used to define events:

Finally, the time range of the dataset on which the event list query will be run, can be restricted (the default is the full epoch range).

The selection criteria are applied in the following order:

  1. find episodes between the start and end thresholds;
  2. reject the episodes shorter than the minimum duration;
  3. merge events separated by less than the dwell time;
  4. calculate the total fluence and peak value for each event;
  5. reject the events for which the peak value is below the minimum value;
  6. subtract the extension from the start time of each event.
The event list search is started when the Run button is pressed. The query can take several minutes, during which no navigation on the server should be possible (please ensure that your browser time-out value is set sufficiently high, e.g. at least to ten minutes).

List name and description

The user should specify a list name (which will be used as a label to identify the model run, for instance on the My SEPEM page) and a description for future reference. The name and description need to be entered prior to pressing the Run button. The model name cannot be left blank. If an event list with the same name is already stored in the database by the current user, the list will be over-written.

Results

When the event list search is completed, the page will reload to display the results. If no events were found, or too many, a message to that effect will be displayed. In this case, please refine the query parameters and try again.

If an acceptable number of events was found, the event list is stored using the specified list name as identifier. In addition, a entry will be made in the user logbook for future reference.

At the bottom of the page, a table is displayed with the start and end times of each event, and the peak and integrated values. In addition, a plot icon is available which displays the data during the respective events.

At the top of the table, links are available to:

The event list can always be consulted on the My SEPEM page.




Last modified on: 4 March 2014.