Lecture37 iq32
1D plane EM waves & Radiation from accelerating a
charged particle
1.
Ch24.h1: 15-16.
1D plane EM waves.
o
Switch on the
current sheet at t=0.
o
B-flux passing
through the front window 12341 and Faraday’s law
o
E-flux passing
through the top area 12561 and Ampere-Maxwell’s law
o
v^2=1/(esp0 x
mu0)
o
Measurement of
esp0 and mu0 in static experiments.
Faraday law and Ampere-Maxwell’s
law enable the propagation of EM waves in
vacuum.
2.
Properties of the
EM waves.
3.
Radiative E field due to acceleration of a point charge.
o
Stationary at A,
there is an isotropic E-field pattern.
o
After a knock. A
kink structure appears in the pattern. It expands outward with the speed of
light.
o
A snapshot at T
i.
The acceleration
zone
ii.
Determine the radiative field at theta, r
iii.
The direction of
the total E field is along the segment 21. (See the proof in Sec24.11 is based on the Gauss’s
law.)
4. The key steps in the derivation.
o
tan (alpha)= Eperp/Eparall
=Eradiative/Ecoul
o
Geometry: tan (alpha)= vT sin(theta)/(c tacc).
o
Complete the
homework problem: ch24.h2 008-012
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