Spiral magneto-electron waves in interstellar gas dynamics

We discuss possible observational consequences resulting from the propagati on of transverse magneto-electron waves in the interstellar medium. We brie fly describe a magnetohydrodynamic model for the cyclotron waves with empha sis on their analogy with hydrodynamic inertial waves. It is shown that the cyclotron waves are heavily damped in the interstellar medium and, therefo re, cannot affect the gas dynamics of star-forming molecular clouds. We dev eloped an analytical model of the helicoidal magneto-electron waves based o n the electromagnetic induction equation for the magnetic flux density driv en by the Hall and Ohmic components of the electric field generated by flow s of thermal electrons. It is established that the helicons can propagate i n the interstellar medium without any noticeable attenuation. The presented numerical estimates for the group velocity of the intercloud helicons sugg est that spiral circularly polarized magneto-electron waves of this type ca n be responsible for the broadening of molecular lines detected from dark i nterstellar clouds. (C) 2001 MAIK "Nauka/ Interperiodica".