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Space physics EF2245 Tomas Karlsson Space and Plasma Physics School of Electrical Engineering. EF2245 Space Physics 2010. Course goals After the course the student should be able to describe and explain basic processes in space plasma physics
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Space physicsEF2245 Tomas Karlsson Space and PlasmaPhysicsSchool of Electrical Engineering EF2245 Space Physics 2010
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. Boström, R., Electrodynamics of the Ionosphere, in Cosmical Geophysics, Ed. Egeland et al. Lyons, L., Formation of Auroral Arcs via Magnetosphere-Ionosphere Coupling, Reviews of Geophysics, 30, 2, 93-112, 1992. Space physics EF2245 EF2245 Space Physics 2010
Do you know MatLab? EF2245 Space Physics 2010
L Ä d - + - - + - + + - - - + + + + + - - - - L + + + + + + - - - - + + + + + + - - - x Plasma frequency EF2245 Space Physics 2010
y x B = Bz z + Single particle motion Consider a charged particle in a magnetic field. Constant acceleration alongz Assume an electric field in the x-z plane: EF2245 Space Physics 2010
Drift motion Average over a gyro period: In general: EF2245 Space Physics 2010
F = 0 F = qE F = mg F = -m grad B Drift motion EF2245 Space Physics 2010
j Lorentz’ force equation Maxwell’s equations Gauss’ law Ohm’s law No magnetic monopoles Energy density Faraday’s law Ampére’s law EF2245 Space Physics 2010
Frozen in magnetic flux PROOF II Magnetic Reynolds number Rm: A B Rm >> 1 Order of magnitude estimate: Frozen-in fields! Rm << 1 Diffusion equation! EF2245 Space Physics 2010
(3) (2) (4) Only consider slow variations (5) Magnetohydrodynamics (MHD) (1) v This together with mass conservation, two of Maxwell’s equations and Ohm’s law make up the most common MHD equations: EF2245 Space Physics 2010
Represents tension along B (1) In equilibrium: Magnetic pressure If magnetic tension = 0 Magnetohydrodynamics (MHD) EF2245 Space Physics 2010
Solar wind Solar corona EF2245 Space Physics 2010
Solar wind properties EF2245 Space Physics 2010
Solar wind properties EF2245 Space Physics 2010
1.4∙10-9 Solar wind properties 1.4∙10-11 1.4∙10-13 1.4∙10-15 Pinterstellar10-13 – 10-14 Pa EF2245 Space Physics 2010
Critical radius for realistic temperatures EF2245 Space Physics 2010
Solar wind solutions EF2245 Space Physics 2010
