The Solar Wind.pdf
The Solar Wind.pdf The Solar Wind.pdf
• Observations of high speed streams– Velocity, densityand protontemperature of twohigh speed streams– Speed andtemperature havesimilar variationswith time– Note that low speedcorresponds to highdensity and viseversaFlow Speed (km/s)Density (cm -3 )Temp. (K)250 7501 10 10010 4 10 5
• The Archimedean spiral associatedwith slow streams is curved morestrongly than for a fast stream.• Because field lines are not allowedto intersect at some point aninteraction region develops betweenfast and slow streams. Since bothrotate with the Sun these are calledcorotating interaction regions(CIR).• On the Sun there is an abruptchange in the solar wind speeds butin space the streams are spread out.• At the interface between fast andslow streams the plasma iscompressed.• The characteristic propagationspeeds (the Alfven speed and thesound speed) decrease.• At some distance between 2AU and3AU the density gradient on bothsides of the CIR becomes large anda pair of shocks develop.• The shock pair propagate awayfrom the interface.– The shock propagating into theslow speed stream is called aforward shock.– The shock propagating into thefast wind is called a reverseshock.
- Page 1 and 2: ESS 200CLectures 6 and 7The Solar W
- Page 3 and 4: • Solar wind speeds (heavy lines)
- Page 5 and 6: • It is useful to describe the so
- Page 8 and 9: • The transition from subsonic to
- Page 10 and 11: • For the solar wind to continue
- Page 12 and 13: • Waves and turbulence?- One poss
- Page 15: • In summary the outer layer of t
- Page 19: ω > Sunv ϕϕSun r r- At large dis
- Page 22: • A meridian view of the IMF- The
- Page 28: • Time series of parameters assoc
- Page 31 and 32: • Plasma measurementsshow a drama
- Page 33 and 34: • A coronal mass ejection in spac
- Page 35 and 36: • The magnetic field configuratio
- Page 37 and 38: •The solar wind forms abubble, ca
- Page 39: • The Voyager passage through the
• Observations of high speed streams– Velocity, densityand protontemperature of twohigh speed streams– Speed andtemperature havesimilar variationswith time– Note that low speedcorresponds to highdensity and viseversaFlow Speed (km/s)Density (cm -3 )Temp. (K)250 7501 10 10010 4 10 5
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