Collision-induced instability at cyclotron harmonics

In this paper, the collision-induced instability at the cyclotron harmonics of the ordinary wave is studied under an assumption ν (v) ∾v^h, where the ν is the collision frequency with the neutral particles and v the electron velocity respectively. When the initial distribution of the electron velocity is a spherical shell in velocity space, it is found that the large value of the Larmor radius and/or wave number relaxes the restriction for the value h which leads to the instability and the growth rate increases with the electron density for the fixed ν and h. (author)