==== http://wiki.keithl.com/SolarWind ====

== Basics of the Solar Wind ==
=== Nicole Meyer-Vernet PSULib QB529.M485 2007 ===
 . [[ https://observatoiredeparis.psl.eu/ | Observatoire de Paris ]]  and [[ https://en.wikipedia.org/wiki/French_National_Centre_for_Scientific_Research | Centre National de la Rechereche Scientifique ]] [[ https://www.cnrs.fr/fr | website ]]
 .p009 Sun: mass 1.98892e30 kg, radius 695700 km, Luminosity 3.828e26 W +/-0.1%
 .p054 plasmas interact less with radiation than with plasmas
 .p057 [[ https://en.wikipedia.org/wiki/Fermi_energy | Fermi energy ]]
  . book's "comet-like" heliosphere model [[ https://www.science.org/doi/10.1126/science.1181079 | obsolete ]]
  . [[ https://www.science.org/doi/10.1126/science.1181079 | Imaging the Interaction of the Heliosphere with the Interstellar Medium from Saturn with Cassini ]]
 .p057 [[ https://pmc.ncbi.nlm.nih.gov/articles/PMC9726803/pdf/11214_2022_Article_939.pdf | heliospheric dust grains ]]
 .p057 plasma particle collisional free path increases strongly with speed, fast particles nearly collisionless
 .p064 Magnetic mirrors: particle moving towards converging/increasing field mirrors and reflects
 .p066 transverse gradient produces a small transverse drift
 .p069  [[ https://en.wikipedia.org/wiki/Vlasov_equation | Vlasov equation ]] [[ https://en.wikipedia.org/wiki/Liouville's_theorem_(Hamiltonian) | Liouville's theorem ]]
 .p080 "upstream kinetic energy converted to downstream [[ https://en.wikipedia.org/wiki/Enthalpy | enthalpy ]], high temperature
 .p083 viscous forces generally much less important than inertial effects, but 
  . see E. M. Purcell [[ https://www.damtp.cam.ac.uk/user/tong/fluids/lowreynolds.pdf | Life at low Reynolds number ]] Am. J. Phys. 45, 3–11 (1977)
 .p083 ions transport momentum, determining viscosity; electrons transport heat, determining thermal conductivity 
 .p084  Reynolds number very large for space plasmas,  viscosity generally negligable
 .p084 1e6 K (kelvin) solar corona heat conductivity 1e4 W/m-K "same order of magnitude as brass" 
  . [[ https://www.researchgate.net/profile/Anastasia_Vasileiou2/publication/263155220/figure/fig4/AS:550876301492239@1508350553460/Brass-CuZn33-properties-as-a-function-of-temperature-a-thermal-conductivity-b_W640.jpg | NO, brass approx. 150 W/m-K ]] Silver around 430 W/m-K
 .p084 conductivity low perpendicular to B, high parallel to B only if mean free path much smaller than scales of variation. 
 .p088 [[ https://en.wikipedia.org/wiki/Magnetic_Reynolds_number | magnetic Reynolds number ]] convection ÷ diffusion
 .p090 magnetic field freezing [[ https://en.wikipedia.org/wiki/Alfv%C3%A9n%27s_theorem |  Alfvén's theorem ]]
 .p090 plasmas in space tied to field lines, do not mix across field
 .p091 magnetized plasma has
  . inertia, corresponding to bulk kinetic energy ½ρV²
  . thermal pressure, corresponding to random kinetic energy ρkT/m
  . magnetic forces, corresponding to B²/2μ₀
 .p092 V = B/(μ₀ρ)½ ≡ V,,A,, [[ https://en.wikipedia.org/wiki/Alfv%C3%A9n_wave#Alfv%C3%A9n_velocity | Alfvén speed ]]
 .p098 [[ https://en.wikipedia.org/wiki/Whistler_(radio) | Whistler ]]
 .p101 Bohr radius (hydrogen atom minimum energy 53e-12 meters, Bohr energy 13.6eV
 .p102 stripping atom  (atomic number Z) of electrons requires approximately Z² × 13.6eV
 .p102 [[ https://en.wikipedia.org/wiki/Saha_ionization_equation | Saha ionization equation ]]
 .p105 cross sections for ionization and recombination 
 .p106 AB⁺  + e⁻ → A + B coefficient of dissociative recombination β ~ 1e-11/√T (units?)
 .p107 Charge exchange A⁺ + B  → A + B⁺, for hydrogen/proton cross section is 2e-19 meters
 .p110 solar wind density 5e6/m³ at 1AU, inverse square with distance
  . velocity 300 to 800 km/s, average 400 km/s, hence 2e12/m²s or 3.3e-15 kg/s 
  . or 0.4 kg/s crossing area of earth disk 
 .p113 sun 2e30 kg, ordinary star mass 0.1 to 100 Suns, smaller is a brown dwarf or giant planet
 .p122 minimum 8e55 protons, 7% of Sun
 .p123 rough estimate maximum 4e58 protons, 40 solar masses, accurate estimate about 80 solar masses
 .p124 graph of solar properties versus radius (scanned from book)
  {{ attachment:SunDepth.png | | width=600 }}
 .p135 maximum granule size 10x scale height, approximately 1500 km
 .p136 solar rotation graph, converted to time period.  Below 0.7 radius, 2.3e6 seconds period
||<-2> diverges above 0.8 radius, at 0.96 radius ||
|| latitude || period Msec ||
|| 0° (eq.) || 2.14        ||
|| 15°      || 2.13        ||
|| 30°      || 2.24        ||
|| 45°      || 2.40        ||
|| 60°      || 2.65        ||
 .p137 Solar magnetism models practically uncomputable, due to Sun's huge magnetic Reynolds number
 .p138 naïve modelling says field decay time 30Gy, reality is a field reversal every 11 years
 .[[ https://www.space.com/the-universe/sun/sun-magnetic-field-flip | 2025 Jan - field reversal soon ]]
 .ref [[ https://iopscience.iop.org/article/10.1086/321493/pdf | JN Bahcall +2 2001: Solar models: Current epoch and time dependences, neutrinos, and helioseismological properties ]]
 .ref [[ https://www.annualreviews.org/content/journals/10.1146/annurev.astro.40.060401.093917 | WB Hubbard +2 2002: Theory of Giant Planets ]] paywall
 .p187 Radiative loss function F(T) ≃ 1e-32 / sqrt(T) W m³

      .'''Book returned to PSU library, no time to dig deep'''

 .p451 Solar parameters
  .radius 7e5 km / mass 2e30 kg / luminosity 3.84e26 W / surface gravity 272 m/s²