space physics ef2245 tomas karlsson space and plasma physics school of electrical engineering ef2245...
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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.
Do you know MatLab?
EF2245 Space Physics 2009
eF m a
F eE
0
E
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
Drift motion
F = 0
F = qE
F = mg
F = -grad B
2drift qB
F Bu
EF2240 Space Physics 2009
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
EF2245 Space Physics 2009
Solar wind properties
EF2245 Space Physics 2009
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
Critical radius for realistic temperatures
EF2245 Space Physics 2009
Solar wind
solutions
EF2245 Space Physics 2009