Gyrotron: The most Suitable Millimeter-Wave Source for Heating of Plasma in Tokamak

In this chapter, brief outline is presented about gyro-devices. Gyro-devices comprise of a family of microwave devices and gyrotron is one among those. Various gyro devices, namely, gyrotron, gyro-klystron and gyro traveling-wave tubes (gyro-TWT) are discussed. Gyrotron is the only microwave source which can generate megawatt range of power at millimeter-wave and sub-millimeter-wave frequency. Gyrotron is the most suitable millimeter wave source for the heating of plasma in the Tokamak for the controlled thermoneuclear fusion reactors. This device is used both for the electron cyclotron resonance heating (ECRH) as well as for the electron cyclotron current drive (ECCD). In this chapter, the basic theory of gyrotron operation are presented with the explanation of various sub-systems of gyrotron. The applications of gyrotrons are also discussed. Also, the present state-of-the-art worldwide scenario of gyrotrons suitable for plasma heating applications are presented in details.

Analysis and Design of 460 GHz Microwave Gyrotron Oscillator

This paper is concerned with the analysis and design of a gyrotron oscillator with 460 GHz that can excite both modes (TE231) the fundamental (230GHz) and (TE061, TE261) second harmonic (near 460GHz). The oscillator is operated with 12KV beam voltage and 100mA beam current, and a computer program was developed to study the cavity in this oscillator and the wave-particle interaction inside it using the forward finite difference technique as a numerical method. The input data of the program are electron energy, velocity ratio, normalized cavity length, the normalized value of the external magnetic field, the mode number (m,n,l), and nth-non van shining root of J_m^' (x)=0 to calculate the beam and starting currents, frequency and quality factor of the cavity. The results show good agreement with other reported works [10]- [12]- [13]- [14], [15] .This oscillator can serve as a millimeter-wave source at the magnetic field of (16.4T) for enhanced nuclear magnetic resonance and can be used to perform the biological experiment.