The wavelengths and attenuation coefficients of dipolar left and
right-hand circularly polarized waves in a radially inhomogeneous axially
magnetized plasma
column are computed by means of step approximation of the radial plasma
density
profile. A comparison with theoretical results assuming radial plasma homogeneity
shows that the radial plasma inhomogeneity is significant for wave propagation.
In
particular, it facilitates the occurrence of backward waves and increases
by up to
one order of magnitude the wave attenuation coefficient compared with a
homogeneous plasma column having the same average plasma density.
Magnetized Plasma-filled Waveguide: A New High-Gradient Accelerating Structure