A Brief Introduction to Space Plasma Physics.pdf - Institute of ...
A Brief Introduction to Space Plasma Physics.pdf - Institute of ... A Brief Introduction to Space Plasma Physics.pdf - Institute of ...
• Radius of circle ( r c ) - cyclotron radius or Larmor radius or gyro radius. v = ρ Ω mv qB – The gyro radius is a function of energy. – Energy of charged particles is usually given in electron volts (eV) – Energy that a particle with the charge of an electron gets in falling through a potential drop of 1 Volt- 1 eV = 1.6X10 -19 Joules (J). • Energies in space plasmas go from electron Volts to kiloelectron Volts (1 keV = 10 3 eV) to millions of electron Volts (1 meV = 10 6 eV) • Cosmic ray energies go to gigaelectron Volts ( 1 geV = 10 9 eV). • The circular motion does no work on a particle r r F ⋅v = r dv m dt r ⋅v ⊥ ρ c = c 1 d( 2 mv = dt 2 ⊥ ) c r r r = qv ⋅( v × B) = 0 Only the electric field can energize particles!
• The electric field can modify the particles motion. – Assume E r ≠ 0 but B r still uniform and F g =0. – Frequently in space physics it is ok to set E r ⋅ B r = 0 • Only E r can accelerate particles along B r • Positive particles go along E and negative particles go along − E • Eventually charge separation wipes out E E ⊥ – has a major effect on motion. • As a particle gyrates it moves along E r and gains energy • Later in the circle it losses energy. • This causes different parts of the “circle” to have different radii - it doesn’t close on itself. r r r E × B = u E 2 B • Drift velocity is perpendicular to and • No charge dependence, therefore no currents E r B r
- Page 1 and 2: ESS 200C - Space Plasma Physics Win
- Page 3 and 4: Space Plasma Physics • Space phys
- Page 5 and 6: - Galileo theorized that aurora is
- Page 7 and 8: The Plasma State • A plasma is an
- Page 9: • B acts to change the motion of
- Page 14 and 15: • The change in the direction of
- Page 16 and 17: • Maxwell’s equations - Poisson
- Page 18 and 19: • Maxwell’s equations in integr
- Page 20 and 21: • For a coordinate in which the m
- Page 22 and 23: B r • The force is along and away
- Page 24: - As particles bounce they will dri
- Page 27 and 28: The Properties of a Plasma • A pl
- Page 29 and 30: • For monatomic particles in equi
- Page 31 and 32: • What makes an ionized gas a pla
- Page 34 and 35: • The plasma frequency - Consider
- Page 36 and 37: • A note on conservation laws - C
- Page 38 and 39: - Momentum equation r ∂us r r r r
- Page 40 and 41: • Energy equation ∂ ( ∂t 1 2
- Page 43 and 44: - Often the last terms on the right
- Page 45 and 46: F B • Magnetic pressure and tensi
- Page 47 and 48: •Some elementary wave concepts -F
- Page 49 and 50: • When the dispersion relation sh
- Page 51 and 52: - Incompressible Alfvén waves •
- Page 53 and 54: 1 2 2 C ⎛ B ⎞ A ⎜ ⎟ ⎝ µ
- Page 55 and 56: - Continuity - Momentum - Equation
- Page 57 and 58: • The fluid velocity must be alon
- Page 59: - Arbitrary angle between k r and B
• The electric field can modify the particles motion.<br />
– Assume E r ≠ 0 but B r still uniform and F g =0.<br />
– Frequently in space physics it is ok <strong>to</strong> set E<br />
r<br />
⋅ B r<br />
= 0<br />
• Only E r<br />
can accelerate particles along B r<br />
• Positive particles go along E and negative particles go<br />
along − E<br />
• Eventually charge separation wipes out E<br />
E ⊥<br />
– has a major effect on motion.<br />
• As a particle gyrates it moves along E r and gains energy<br />
• Later in the circle it losses energy.<br />
• This causes different parts <strong>of</strong> the “circle” <strong>to</strong> have different radii -<br />
it doesn’t close on itself.<br />
r r<br />
r E × B<br />
=<br />
u E<br />
2<br />
B<br />
• Drift velocity is perpendicular <strong>to</strong> and<br />
• No charge dependence, therefore no currents<br />
E r<br />
B r
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