Solar energetic particles
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Solar energetic particles (SEP), formerly known as solar cosmic rays, are
SEPs are relevant to the field of
History
SEPs were first detected in February and March 1942 by Scott Forbush indirectly as ground level enhancements.[1]
Solar particle events
SEPs are accelerated during
Two main mechanisms of acceleration are possible: diffusive shock acceleration (DSA, an example of second-order Fermi acceleration) or the shock-drift mechanism. SEPs can be accelerated to energies of several tens of MeV within 5–10 solar radii (5% of the Sun–Earth distance) and can reach Earth in a few minutes in extreme cases. This makes prediction and warning of SEP events quite challenging.
In March 2021, NASA reported that scientists had located the source of several SEP events, potentially leading to improved predictions in the future.[2][3]
Research
SEPs are of interest to scientists because they provide a good sample of solar material. Despite the nuclear fusion occurring in the core, the majority of solar material is representative of the material that formed the solar system. By studying SEP's isotopic composition, scientists can indirectly measure the material that formed the solar system.
See also
References
- .
- ^ Hatfield, Miles (2021-03-10). "Scientists Trace Fastest Solar Particles Back to the Sun". NASA. Retrieved 2021-03-15.
- PMID 33658205.
- Reames, Donald V. (2013). "The Two Sources of Solar Energetic Particles". Space Science Reviews. 175 (1–4): 53–92. S2CID 255072537.
- Reames D.V., Solar Energetic Particles, Springer, Berlin, (2017a) ISBN 978-3-319-50870-2, doi: 10.1007/978-3-319-50871-9.