The STEREO/HET Electron Event List Notes

A. Labrador, Caltech
Last updated 3/19/26.

The STEREO/HET Ahead and Behind event lists are generated from the 0.7-1.4 MeV 1 hour average intensities, available in the ASCII data files at the HET Data and Plots pages here. The event-logging code scans through this intensity data linearly.

For an event to be logged,

• The intensity must exceed a threshold (0.05 particles/cm^2 s sr MeV)
• The intensity must exceed this threshold for at least 3 points. Note that this is points, not hours, as some time periods have skips.
• The start of the event is the first point above threshold.
• The event continues as long as the points are above threshold.
• The end of the event is the last point above threshold.
• If the event length exceeds 0.2 days (~4.8 hours), its plot is saved and linked from the .html lists and the .csv file.
• If the event length exceeds 12 points above minimum, it is defined as a "long" event.
• After a long event, the next event must exceed 12 points above threshold (instead of 3). After 12 points beyond the end of the last long event, the points above threshold minimum is returned to 3. The purpose of this long event threshold, short event filter, is to reduce the long tails of some events bouncing above and below threshold from counting as multiple small events.

To run on SRL machines:

The primary code is in /home/stereo/labrador/stereo_het_electron_events. Edit the top of plot_het_ascii_data.idl to change the last dates for execution of plot_het_ascii_data.pro. STEREO Behind ends on 12/12/14, but STEREO Ahead continues through 2025. The last three parameters passed to plot_het_ascii_data.pro are YYYY, MM, DD.

Execute the code with

idl plot_het_ascii_data.idl

When it's done, the following files or folders can be copied to /home/labrador/public_html:

changelog.html
HET_electron_plots_Ahead/
HET_electron_plots_Behind/
notes.html
the_event_list_combined.csv
the_event_list_combined.txt
the_event_list_HET_Ahead_electrons.html
the_event_list_HET_Behind_electrons.html
the_event_list_HET_combined_electrons.html
the_event_list_HET_electrons.html
the_event_list.html