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Space physicsEF2245
Tomas Karlsson
Space and PlasmaPhysics
School of Electrical Engineering
EF2245 Space Physics 2009
Activity Date Time Room Subject Litterature
L1 27/10 10-12 Sem. Introduction, Solar wind KR Ch. 1-2, 4 L2 29/10 15-17 Sem. Solar wind, cont., Shocks KR Ch. 4, 5 T1 30/10 15-17 Sem. CANCEL-LED!
3/11 10-12
L3 5/11 15-17 Sem. Solar wind interaction with celestial bodies
KR Ch. 6, 8, 15 (p 503-510)
Distribution of Assignment 1
5/11
T2 6/11 15-17 Sem. L4 10/11 10-12 Sem. Ionospheres KR Ch. 7 T3 12/11 15-17 Sem. Deadline, Assignment 1
13/11 13.00
L5 13/11 13-15 Sem. The magnetopause and magnetotail
KR Ch. 9
L6 17/11 10-12 Sem. The magnetosphere and its dynamics
KR Ch. 10, 13
Distribution of Assignment 2
13/11
T4 19/11 15-17 Sem. Deadline, Assignment 2
19/11 15.00
L7 24/11 10-12 Sem. ULF pulsations and global oscillations of the magnetosphere
KR Ch. 11, 14
T5 26/11 15-17 Sem. L8 1/12 10-12 Sem. Auroral physics KR Ch. 14,
extra material L9 8/12 10-12 Sem. Auroral physics, cont. KR Ch. 14,
extra material T6 3/12 15-17 Sem. Distribution of home examination
8/12
Deadline, home examination
18/12 24.00
Space physics EF2245
EF2245 Space Physics 2009
Course goals
After the course the student should be able to
• describe and explain basic processes in space plasma physics
• use established theories to estimate quantitatively the behaviour of some of these processes
• make simple analyses of various types of space physics data to compare with the quantitative theoretical predictions
• describe some hot topics of today’s space physics research
Litterature
Kivelson, M.G., and C. T. Russel (ed.), Introduction to Space Physics, Cambridge Univeristy Press.
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F eE
0
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een x
sin( )pex t
2
0
epe
e
n e
m
2 2
20
e
e
n e x d x
m dt
L
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L
x
d
EF2240 Space Physics 2009
Plasma frequency
Single particle motion
EF2240 Space Physics 2009
,0,x zE EE
Consider a charged particle in a magnetic field.
y
xB = Bz z
+
Assume an electric field in the x-z plane:
dm q
dt
vv B E
xy x
yx
zz
dvm qv B qE
dtdv
m qv Bdt
dvm qE
dt
Constant acceleration along z
22
2
2 22
2 2
y yxg g x
y x xg g y x
dv dvd v qBv
dt m dt dt
d v dv dvqB q Bv E
dt m dt dt m
Drift motion
EF2240 Space Physics 2009
22
2
2 22
2 2
y yxg g x
y x xg g y x
dv dvd v qBv
dt m dt dt
d v dv dvqB q Bv E
dt m dt dt m
22
2
2
22
xg x
xy
xg y
d vv
dtE
d vEB
vdt B
g x
g y
i t
x
i txy
v v e
Ev v e
B
Average over a gyro period:
, 2 2
yx x zdrift y
E E Bv
B B B
E B
In general:
2 2 2drift
q
B qB qB
E B E B F Bv
Maxwell’s equations
0 B
t
B
E
0 0 0 t
E
B j
Gauss’ law
No magnetic monopoles
Faraday’s law
Ampére’s law
Lorentz’ force equation
( )q F E v B
Ohm’s law
j E
j
yx zAA A
x y z
A
, ,y yx xz zA AA AA A
y z z x x y
A
Energy density2 2
00
,2 2B E
B EW W
0
E
EF2245 Space Physics 2009
Frozen in magnetic flux PROOF II
2
0
1
t
B
v B B
A B
Order of magnitude estimate:
0
22
0 0
1 m
v BA L vL R
BBL
v B
B
Magnetic Reynolds number Rm:
Rm >> 1 t
B
v B
2
0
1
t
B
BRm << 1
Frozen-in fields!
Diffusion equation!
EF2245 Space Physics 2009
This together with mass conservation, two of Maxwell’s equations and Ohm’s law make up the most common MHD equations:
Magnetohydrodynamics (MHD)
dp
dt
pt
vj B f
vv v j B f (1) ( ) j E v B(3)
0 0 t
EB j(4)
Only consider slow variations
t
B
E(5)
EF2245 Space Physics 2009
v
0t
v(2)
Magnetohydrodynamics (MHD)
dp
dt
vj B(1)
In equilibrium:
0 p j B
0
10p
B B
2
0 0
10
2
Bp
B B
Represents tension along B
If magnetic tension = 0
2
02
Bp konst
Magnetic pressure
EF2245 Space Physics 2009
Solar wind
EF2245 Space Physics 2009
Solar corona
Solar wind properties
1.4∙10-9
1.4∙10-11
1.4∙10-13
1.4∙10-15
Pinterstellar 10-13 – 10-14 Pa
EF2245 Space Physics 2009