EXPERIMENTAL INVESTIGATION OF PLASMA MICROINSTABILITIES IN CROSSED MAGNETIC AND AC ELECTRIC FIELDS,
Abstract
An anisotropic electron velocity distribution was produced in a magnetized plasma by means of an intense AC electric field near the cyclotron resonance. Unstable electrostatic waves associated with such a distribution were investigated theoretically and confirmed experimentally using the combination scattering technique. In particular, waves near the second harmonic of the electron motion imposed by the AC field were studied in detail. Their dependence on the plasma density was measured and very good agreement with the theory was obtained. Experimental observations showed that the waves were stimulated by the external AC power at least in low plasma densities. At higher plasma densities there was evidence of self-excitation. The growth rates were measured. Cyclotron harmonic electrostatic waves associated with the Maxwellian distribution, (in the absence of the AC field), were observed by means of the same technique. They were excited near the second harmonic by an extraordinary electromagnetic wave which was weakly coupled to the plasma and therefore did not perturb the thermal distribution. Qualitative agreement with the theory and other related experiments was obtained in this case. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1967
- Accession Number
- AD0667548
Entities
People
- Alexandros J. Anastassiades
Organizations
- Columbia University