The Solar Wind.pdf

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• Let us express the magnetic field in the equatorialrplane in polar coordinates as B = B , B )(r ϕ1 ∂ 2– Gauss’s Law in spherical coordinates is ∇ ⋅ B r = r2 r=r ∂rB2 2since the field depends only on r so that r B = .rr0B0– The magnetic flux through radial shells is conserved and the radialcomponent of the field decreases as2⎛ r0⎞B r= B0⎜⎟⎝⎠r r– The frozen-in field condition ∇×( v × B)= 0 gives1 ∂( r(vϕ Br− vrB ϕ)) = 0r ∂ror r( v B v B )) const.If we assume thatϕ r−r ϕ=get2rvϕ Br− rvrBϕ=BϕB=ϕrvϕv=Bϕr− r20rvr− rωvrr 0ω BB ω0Sun BrSunSun0B r( ) 0is radial at r 0we
ω > Sunv ϕϕSun r r– At large distances and B ≈ − rωB v .– The radial component falls off as r -2 while the azimuthal componentfalls off as r -1.2( B r)0 0 1 ⎛ω2⎟ ⎞SunrB r = +⎜r ⎝ vr⎠• The angle between the magnetic field direction and the radiusvector from the Sun is tanψ = B ϕB r. For typical solar windparameters at the Earth it is about 45 0 with respect to the radialdirection.• The stretched out heliospheric configuration is maintained by anequatorial current sheet. The magnetic field lines and currentlines are sketched below.
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 22: • A meridian view of the IMF- The
Page 26 and 27: • Observations of high speed stre
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

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