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paraxial approximation
microwave horn
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z Eq Hj r I DL y j x
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far field
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x y z ’ x’, y’ a b uniform illumination
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Be careful with the procedure of calculating the limits on the integration – this is an anomaly and it is not a real effect!
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b a microwave horn
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b a p. 624 ?
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b a limits??
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plasma
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Waves in plasmas– high frequency
Only electrons can move! Mi > > me
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Waves in plasmas– high frequency
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Waves in plasmas– high frequency
Derive a wave equation > pe
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Microwave experiment x z y a b I ne E E ne r resonances
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Waves in plasmas– low frequency – normalized variables
Equation of continuity for the ions Equation of motion for the ions Electrons can respond quickly to electric fields and we can assume that their density is given by a Maxwell-Boltzmann relation. Poisson’s equation Electrostatic approximation
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Waves in plasmas– low frequency
b
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Linear experiments Vacuum chamber to reduce collisions plasma creation
Ion acoustic wave excitation, propagation, and detection
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Waves in plasmas– low frequency
z t ???
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Nonlinear fluid equations for ion motion
Mel Widner Ph.D. thesis
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What about the following experiment?
Reflection ???
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w
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Nonlinear ion acoustic solitons
Scott-Russell experiment 1834 KdV equation 1895 Recurrence calculation 1960 Nonlinear plasma equations KdV equation Plasma experiments
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Plasma experiment
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Experimental results
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In order to minimize this energy, V must be a solution of Laplace’s equation.
Let there be another solution U that satisfies the boundary conditions. Linear media implies superposition!
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Either V is specified (U= 0) or the normal derivative of V = 0.
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