We are reporting the discovery of a new radio analysis for studying
plasma magnetic fields. In the high frequency regime, wherein the
electromagnetic wave frequency exceeds the plasma and cyclotron
frequencies, propagating electromagnetic waves assume four different
plasma wave modes: (1) the ordinary “O-mode” (present with/without a
magnetic field), (2) the right-handed circularly polarized “RCP-mode”
(parallel to magnetic field), (3) the left-handed circularly polarized
“LCP-mode” (parallel to magnetic field), and (4) the extra-ordinary
“X-mode”. The X-mode occurs when the magnetic field is perpendicular
to the electromagnetic wave propagation direction. Until now, the X-mode
has not been studied. For applications such as total electron content
measurements, the X-mode is a source of error. We show how to isolate
this effect, eliminating the error as well as enabling the magnetic
field to be studied. This also enables the remote measurement of total
magnetic field strength when used in combination with Faraday rotation.