Differences between revisions 1 and 7 (spanning 6 versions)
⇤ ← Revision 1 as of 2019-09-17 21:02:01 →
Size: 619
Editor: KeithLofstrom
Comment:
← Revision 7 as of 2019-09-17 22:04:53 → ⇥
Size: 1062
Editor: KeithLofstrom
Comment:
Deletions are marked like this. Additions are marked like this.
Line 2: Line 2:

 .[[ https://en.wikipedia.org/wiki/Solar_wind#cite_note-kallenrode-28 | WP ref ]] 1.3e36 particles per second, presumed monatomic hydrogen		  * 1.3e36 particles per second, presumed monatomic hydrogen
  . [[ https://en.wikipedia.org/wiki/Solar_wind#cite_note-kallenrode-28 | WP ref ]]
Line 6: Line 6:
  . slow wind 300–500 km/s, temperature ~1e5 K, twice as dense → 5e-15 kg/(m²-s)
  . fast wind 750 km/s, temperature ~8e5 K, half as dense → 3e-15 kg/(m²-s)
   . [[ https://web.archive.org/web/20080610125820/http://solarscience.msfc.nasa.gov/suess/SolarProbe/Page1.htm | WP ref ]]		  * slow wind 300–500 km/s, temperature ~1e5 K, twice as dense → 5e-15 kg/(m²-s)
  . RMS isotropic thermal velocity ~50 km/s
   . RMS isotropic thermal velocity = sqrt( 3 k T / m ) ≈ 0.157 km/s * sqrt( T )
 * fast wind 750 km/s, temperature ~ 8e5 K, half as dense → 3e-15 kg/(m²-s)
  . RMS isotropic thermal velocity ~140 km/s
  . [[ https://web.archive.org/web/20080610125820/http://solarscience.msfc.nasa.gov/suess/SolarProbe/Page1.htm | WP ref ]]
 * estimated H cross section ≈ 0.5 Ų = 5e-21m²; 5e12 H/(m²-s) * 5e-21m² → 25e-9 H collisions per second → 0.8 collisions per year
  . That's against a zero radius target - for a hydrogen target 3 collisions per year, for an oxygen target many per year

Solar Wind

  • 1.3e36 particles per second, presumed monatomic hydrogen

    • WP ref

    • Area at 1 AU = 4π ( 150e9m )² = 2.8e23 m², hence flux = 1.3e36 H/s / 2.8e23 m² ≅ 5e12 H/(m²-s)
    • Hydrogen mass 1.67e-27 kg, mass flux - 8e-15 kg/(m²-s)
  • slow wind 300–500 km/s, temperature ~1e5 K, twice as dense → 5e-15 kg/(m²-s)
    • RMS isotropic thermal velocity ~50 km/s
      • RMS isotropic thermal velocity = sqrt( 3 k T / m ) ≈ 0.157 km/s * sqrt( T )
  • fast wind 750 km/s, temperature ~ 8e5 K, half as dense → 3e-15 kg/(m²-s)
    • RMS isotropic thermal velocity ~140 km/s

    • WP ref

  • estimated H cross section ≈ 0.5 Ų = 5e-21m²; 5e12 H/(m²-s) * 5e-21m² → 25e-9 H collisions per second → 0.8 collisions per year
    • That's against a zero radius target - for a hydrogen target 3 collisions per year, for an oxygen target many per year

SolarWind (last edited 2019-09-17 22:04:53 by KeithLofstrom)