NUMERICAL STUDY OF THE DETAILED STRUCTURE OF THE ION RESONANCE CONE

The detailed structure of ion resonance cone radiated by a point sourc e antenna in a warm magnetized plasma at a frequency lower than the io n cyclotron frequency is numerically investigated. Aside from the exis tence of the previously reported ion resonance cone, an axial modulati on of the amplitude of the radiated potential in the direction paralle l to the magnetic field is shown to be always present. The modulation length is related to the frequency value and to the electron to ion te mperature ratio through the peculiar shape of the dispersion surface. This result, together with the fact that the constant-phase conical su rfaces have an aperture angle very different from the resonance cone a ngle, can provide an effective way to estimate the ion temperature.