# I Particle calculation during a solar proton event

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1. Aug 2, 2017

### yoyopizza

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. Aug 2, 2017

### Staff: Mentor

Where does your estimate for the solid angle come from? It corresponds to a source size of just about 150 meters.

3. Aug 2, 2017

### davenn

top left of this well known site gives the current conditions
http://www.spaceweather.com/

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

Dave