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Regarding seed population input

  • The seed population not only affects the magnitude of fluence, but also affects the spectral break energies, so it’s not a free parameter.
  • We use injection efficiency (percentage of background protons with high enough energies to go through DSA) to reflect seed population density. Need to set it on-the-fly for prediction runs.
  • We first try different injection efficiency settings on Mar 07, 2012 event. Find the value with good agreement with observation as reference (0.4%)
  • We calculate the 0.1 MeV fluence from the ACE-EPAM fittings provided by the SEP scoreboard, divide it by the total solar wind density. Then we compare this value to Mar 07, 2012 event to set the injection efficiencies for all other events.
  • This data is at 1 AU. We have little knowledge of the radial evolution at closer distances.

(From SHINE SEP validation challenge website)

(Spectral break location changes with different injection efficiency values)

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Input parameters for the scoreboard events

  • 1AU Solar wind parameters from OMNI data
  • CME speed is the average between CME 3D velocity and Plane of sky velocity
  • Longitude is the average between CME longitude and Flare longitude
  • Yellow values are fine-tuned within the range given by the scoreboard input parameters
  • Red values are what I find not reliable on the scoreboard

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Example Integral flux results

(The 0.1 MeV proton fluence for April 11, 2013 event is too small (20x smaller than 07mar2012), so we used the default value)

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Mar 07, 2012 Event, Effect of perpendicular diffusion

No Perpendicular Diffusion

Perpendicular Diffusion Included

(CME center longitude set at E20)

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July 12, 2012 Event: Effect of CME speed

CME speed = 885 km/s

(Plane of sky velocity on scoreboard)

CME speed = 1400 km/s

(CME 3d velocity on scoreboard)

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Jan 06/07, 2014 Event, Twin CME

  • These two events are modeled separately
  • Missing flare info for Jan 6 event
  • CME width seems too large for Jan 6.
  • Change CME longitude can improve the early rising phase for Jan 7 event.

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July 14, 2017 event: a very weak event

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Conclusions

  • The way we decide suprathermal input based on 0.1 MeV proton fluence gives reasonable results across all events.
  • Onset time from iPATH is off by a certain amount of time, especially for events with slower CMEs.
  • The prediction simulation results are only as good as the input parameters. Suprathermal seed population input, CME speed, and CME center longitudes are the most important input parameters.