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I Particle calculation during a solar proton event

  1. Aug 2, 2017 #1
    Trying to figure out how many particles would bombard an astronaut during a solar proton event. Given that the most possible is around 43,000 particle flux units (pfu) according to NASA.
    First calculating steradians, assuming a person is 1m^2, 1/(1E9)^2=1E-18.
    My calculation yields (43000 pfu)(10^4 cm^2)(10^-18 steradians)(1day) = 0.0000371 protons, which does not seem to be accurate, as I am led to believe by how deadly these solar proton events are supposed to be. If 0.0000371 protons is the max while most events have pfu's less than 100, I think something must be wrong with this calculation, likely the steradian part. Thoughts?

    Thank you
  2. jcsd
  3. Aug 2, 2017 #2


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    Staff: Mentor

    Where does your estimate for the solid angle come from? It corresponds to a source size of just about 150 meters.
  4. Aug 2, 2017 #3


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    the info is readily available and considering your tagged your thread "I", I'm surprised you haven't done your research

    top left of this well known site gives the current conditions

    At the time of writing this it was
    Solar Wind speed: 371.9 km/sec
    Wind density: 3.8 protons/cm3

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