Axial modes in terahertz high-harmonic large-orbit gyrotrons

2019 ◽  
Vol 33 (14n15) ◽  
pp. 1940008
Author(s):  
Yi Sheng Yeh ◽  
Cong-Yuan Zheng ◽  
Li-Jhen Li ◽  
Po-Yi Chiang ◽  
Yen-Cheng Chen ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Applied Magnetic Field ◽  
High Harmonic ◽  
Mode Competition ◽  
Velocity Spread ◽  
Axial Mode ◽  
Third Harmonic ◽  
Large Orbit Gyrotron ◽  
Text Mode

Terahertz (THz) gyrotrons can operate with a lower applied magnetic field in harmonic operation, but the weakened harmonic interactions in harmonic gyrotrons can introduce serious challenges when mode competition occurs. The use of an axis-encircling electron beam can greatly alleviate mode competition in a harmonic gyrotron. In this paper, we study axial modes for third-harmonic [Formula: see text]-mode large-orbit gyrotrons. Simulation results reveal that the minimum current for oscillation to begin in each axial mode in the gyrotron regime is associated with a specific range of applied magnetic field. To avoid mode competition, tapered applied magnetic fields and waveguide radii are employed to enhance the high-order axial modes and suppress the low-order axial modes. Furthermore, spurious transverse modes in a THz gyrotron are discussed below. A stable third-harmonic [Formula: see text]-mode large-orbit gyrotron at the third-order axial mode is predicted to yield peak output power of 6.5 kW at 768.1 GHz with an efficiency of 10% for a 75-kV, 0.85-A electron beam with an axial velocity spread of 3%.

Electron Beam Misalignment Study of MIG for 42 GHz, 200 kW Gyrotron

Frequenz ◽  
2017 ◽  
Vol 71 (11-12) ◽  
Author(s):  
S. K Sharma ◽  
Udaybir Singh ◽  
Nitin Kumar ◽  
Naveen Sahu ◽  
Narendra Shekhawat ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Axial Velocity ◽  
Transverse Velocity ◽  
Velocity Ratio ◽  
Velocity Spread ◽  
Design Parameters ◽  
Simulation Results

AbstractThis paper presents the electron beam misalignment study with respect to cathode position and cathode magnetic field of 42 GHz, 200 kW gyrotron. The performance of gyrotron is affected with the misalignment of cathode position. The simulation results confirm the tolerance of cathode misalignment with respect to the design parameters such as the transverse-to-axial velocity ratio, the maximum transverse velocity spread, etc.

scholarly journals Prospective THz Gyrotrons for High-Field Magneto-Resonance Spectroscopy

2018 ◽  
Vol 195 ◽  
pp. 01003
Author(s):  
V.L. Bratman ◽  
A.E. Fedotov ◽  
Yu.K. Kalynov ◽  
V.N. Manuilov
Keyword(s):  
Magnetic Fields ◽  
Harmonic Generation ◽  
High Field ◽  
Low Voltage ◽  
High Harmonic ◽  
Third Harmonic Generation ◽  
Resonance Spectroscopy ◽  
Magnetron Injection Gun ◽  
Third Harmonic ◽  
Large Orbit Gyrotron

A high-harmonic Large Orbit Gyrotron and a low-voltage gyrotrino placed inside a spectrometer cryomagnet enable greatly simplify terahertz systems for magneto-resonance spectrometers. Large Orbit Gyrotrons provide a powerful third-harmonic generation at frequencies of 1 THz and 0.394 THz in pulsed and CW regimes, respectively, at significantly lower magnetic fields than conventional gyrotrons. According to simulations the gyrotrino with the voltage of 1.5 kV and frequency of 0.264 THz can generate a power of tens of watts; a possibility to operate at such a low voltage is demonstrated in the existing gyrotron with three-electrode magnetron-injection gun.

scholarly journals Stagnation of electron flow by a nonlinearly generated whistler wave

2017 ◽  
Vol 83 (2) ◽  
Author(s):  
Toshihiro Taguchi ◽  
Thomas M. Antonsen ◽  
Kunioki Mima
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Applied Magnetic Field ◽  
Large Amplitude ◽  
Cold Plasma ◽  
Relativistic Electron Beam ◽  
Electron Flow ◽  
Magnetized Plasma ◽  
Beam Transport ◽  
Electron Beam Transport

Relativistic electron beam transport through a high-density, magnetized plasma is studied numerically and theoretically. An electron beam injected into a cold plasma excites Weibel and two-stream instabilities that heat the beam and saturate. In the absence of an applied magnetic field, the heated beam continues to propagate. However, when a magnetic field of particular strength is applied along the direction of beam propagation, a secondary instability of off-angle whistler modes is excited. These modes then couple nonlinearly creating a large amplitude parallel-propagating whistler that stops the beam. Here, we will show these phenomena in detail and explain the mechanism of whistler mediated beam stagnation.

Materials for Electron Beam Information Storage

1969 ◽  
Vol 27 ◽  
pp. 152-153 ◽  
Author(s):  
D. E. Speliotis
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Recent Literature ◽  
Electron Beams ◽  
Information Storage ◽  
The Subject ◽  
The Magnetic Field

The interaction of electron beams with a large variety of materials for information storage has been the subject of numerous proposals and studies in the recent literature. The materials range from photographic to thermoplastic and magnetic, and the interactions with the electron beam for writing and reading the information utilize the energy, or the current, or even the magnetic field associated with the electron beam.

Sign in / Sign up

Export Citation Format

Share Document