Numerical Modeling of Harmonic Auto-resonance Peniotron (HARP)

• Published in: IEEE International Conference on Plasma Science, 1991 p. 183
• Main Authors: Ahn, S., Ganguly, A.K.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 1991
• Subjects: Cyclotrons; Dielectric losses; Electrons; Frequency; Gyrotrons; Klystrons; Laboratories; Magnetic fields; Microwave devices; Plasma devices
• ISBN: 9780780301474; 0780301471
• DOI: 10.1109/PLASMA.1991.695710

The amplifier source of high efficiency and high power is in demand in the millimeter wave frequency. The gyro-TWT operating at the fundamental cyclotron mode can meet these conditions at the cost of using high magnetic field. The magnetic field can be reduced by operating at high harmonic cyclotron mode but with reduced efficiency. The peniotron was introduced to improve the efficiency, and the HARP does increase it even further. As used in the cyclotron auto-resonance maser (CARM), the same concept of nearly locked resonance condition is able to be used in the HARP when the interaction takes place near the velocity of light line. The frequency remains nearly constant in the dispersion diagram during the evolution passage of decreasing kinetic energy of beam electrons. There is a remarkable difference between the CARM and HARP in their instability characteristics. CARM exhibits a negative mass type of instability and shows a corresponding bunching pattern in the phase. However the HARP follows the drift induced instability due to B rƒ x v ⊥. in the geometric space. The nonlinear evolution of the HARP is investigated numerically for the axis encircling electron beam. The set of coupled nonlinear differential equations which govern the self-consistent evolution of the TE modes and the trajectories of an ensemble of electrons in a peniotron are solved subject to usual boundary conditions as in the gyrotron amplifier simulation. The space charge effects are neglected in the analysis. We will present numerical results of the efficiency and power of the HARP for the cylindrical and slotted waveguide structures in this presentation.