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.

Cyclotron harmonic wave propagation and instabilities: II. Oblique propagation

1970 ◽  
Vol 4 (2) ◽  
pp. 249-264 ◽  
Author(s):  
J. A. Tataronis ◽  
F. W. Crawford
Keyword(s):  
Magnetic Field ◽  
Wave Propagation ◽  
Axial Velocity ◽  
Transverse Velocity ◽  
Harmonic Wave ◽  
High Energy ◽  
Velocity Spread ◽  
Oblique Propagation ◽  
Longitudinal Wave Propagation ◽  
Cyclotron Harmonic

Part I of this paper has discussed longitudinal wave propagation, perpendicular to the static magnetic field, in a warm homogeneous magnetoplasma. Part II extends the work to oblique propagation. The ring and Maxwellian transverse velocity distributions, which are absolutely unstable and stable, respectively, for perpendicular propagation, are shown here to be both absolutely unstable for oblique propagation. Their instabilities are radically affected by the introduction of axial velocity spread. A detailed study is made for the cases of a Maxwellian transverse distribution with resonance and resonance-squared axial velocity distributions. It is shown that abolute instabilities occur at high energy anisotropies. These become convectively unstable as teh anistropy is reduced, and are quenched as isotropy is approached. The isotropic Maxwellian is treated in detail, and shows both cyclotron and Landau collisionless damping.

Simulation of No-Load Voltage of Single Phase Synchronous Generator Based on ANSYS

2011 ◽  
Vol 268-270 ◽  
pp. 231-234
Author(s):  
Jing Yang ◽  
Wei Jun Wang ◽  
Yong Gang Zuo ◽  
Ping Feng ◽  
Long Bo Mao
Keyword(s):  
Magnetic Field ◽  
Power Supply ◽  
Single Phase ◽  
Synchronous Generator ◽  
Simulation Method ◽  
Design Parameters ◽  
Test Results ◽  
Load Voltage ◽  
Simulation Results

The theory and method of analyzing the no-load magnetic field of single phase synchronous generator(SPSG) is presented in this article, and the no-load voltage of SPSG is simulated based on ANSYS program. The no-load voltage simulation results of a SPSG resemble its test results, which prove the simulation method in this article is correct and effective. The simulation results can provide theoretical bases and method for engineers in optimizing the design parameters to improve the power supply quality of SPSG.

Simulation for Aberration of Chromium Atomic Beam Focusing and Deposition

2011 ◽  
Vol 189-193 ◽  
pp. 4191-4194
Author(s):  
Wen Tao Zhang ◽  
Jing Huang ◽  
Bao Hu Zhu ◽  
Yuan Yuan Wu ◽  
Xi Huang
Keyword(s):  
Atomic Beam ◽  
Spherical Aberration ◽  
Transverse Velocity ◽  
Critical Role ◽  
Chromatic Aberration ◽  
Image Distortion ◽  
Velocity Spread ◽  
Focal Line ◽  
Beam Focusing ◽  
Simulation Results

The image distortion which comes from aberration is analyzed and the effects on focal line features are also discussed, which are resulted from the spherical aberration, chromatic aberration and beam spread. The simulation results have show that source imperfection, especially the transverse velocity spread, plays a critical role in broadening the feature width.

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%.

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.

scholarly journals Simulations of Switchback, Fragmentation and Sunspot Pair in δ-Sunspots during Magnetic Flux Emergence

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 586
Author(s):  
Che-Jui Chang ◽  
Jean-Fu Kiang
Keyword(s):  
Magnetic Field ◽  
Solar System ◽  
Field Strength ◽  
Magnetic Flux ◽  
Initial Conditions ◽  
Observation Data ◽  
Flux Emergence ◽  
Polarity Inversion ◽  
Simulation Results ◽  
Spot Type

Strong flares and coronal mass ejections (CMEs), launched from δ-sunspots, are the most catastrophic energy-releasing events in the solar system. The formations of δ-sunspots and relevant polarity inversion lines (PILs) are crucial for the understanding of flare eruptions and CMEs. In this work, the kink-stable, spot-spot-type δ-sunspots induced by flux emergence are simulated, under different subphotospheric initial conditions of magnetic field strength, radius, twist, and depth. The time evolution of various plasma variables of the δ-sunspots are simulated and compared with the observation data, including magnetic bipolar structures, relevant PILs, and temperature. The simulation results show that magnetic polarities display switchbacks at a certain stage and then split into numerous fragments. The simulated fragmentation phenomenon in some δ-sunspots may provide leads for future observations in the field.

scholarly journals Stability of a Viscous Liquid Jet in a Coaxial Twisting Compressible Airflow

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 918
Author(s):  
Li-Mei Guo ◽  
Ming Lü ◽  
Zhi Ning
Keyword(s):  
Viscous Liquid ◽  
Axial Velocity ◽  
Liquid Velocity ◽  
Velocity Ratio ◽  
Dominant Mode ◽  
Liquid Jet ◽  
Axisymmetric Mode ◽  
Jet Instability ◽  
Jet Stability ◽  
Jet Breakup

Based on the linear stability analysis, a mathematical model for the stability of a viscous liquid jet in a coaxial twisting compressible airflow has been developed. It takes into account the twist and compressibility of the surrounding airflow, the viscosity of the liquid jet, and the cavitation bubbles within the liquid jet. Then, the effects of aerodynamics caused by the gas–liquid velocity difference on the jet stability are analyzed. The results show that under the airflow ejecting effect, the jet instability decreases first and then increases with the increase of the airflow axial velocity. When the gas–liquid velocity ratio A = 1, the jet is the most stable. When the gas–liquid velocity ratio A > 2, this is meaningful for the jet breakup compared with A = 0 (no air axial velocity). When the surrounding airflow swirls, the airflow rotation strength E will change the jet dominant mode. E has a stabilizing effect on the liquid jet under the axisymmetric mode, while E is conducive to jet instability under the asymmetry mode. The maximum disturbance growth rate of the liquid jet also decreases first and then increases with the increase of E. The liquid jet is the most stable when E = 0.65, and the jet starts to become more easier to breakup when E = 0.8425 compared with E = 0 (no swirling air). When the surrounding airflow twists (air moves in both axial and circumferential directions), given the axial velocity to change the circumferential velocity of the surrounding airflow, it is not conducive to the jet breakup, regardless of the axisymmetric disturbance or asymmetry disturbance.

scholarly journals Double layers in the downward current region of the aurora

2003 ◽  
Vol 10 (1/2) ◽  
pp. 45-52 ◽  
Author(s):  
R. E. Ergun ◽  
L. Andersson ◽  
C. W. Carlson ◽  
D. L. Newman ◽  
M. V. Goldman
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Phase Space ◽  
Electric Field ◽  
Electric Fields ◽  
Double Layers ◽  
Parallel Electric Field ◽  
Electrostatic Waves ◽  
Current Region ◽  
Decisive Evidence

Abstract. Direct observations of magnetic-field-aligned (parallel) electric fields in the downward current region of the aurora provide decisive evidence of naturally occurring double layers. We report measurements of parallel electric fields, electron fluxes and ion fluxes related to double layers that are responsible for particle acceleration. The observations suggest that parallel electric fields organize into a structure of three distinct, narrowly-confined regions along the magnetic field (B). In the "ramp" region, the measured parallel electric field forms a nearly-monotonic potential ramp that is localized to ~ 10 Debye lengths along B. The ramp is moving parallel to B at the ion acoustic speed (vs) and in the same direction as the accelerated electrons. On the high-potential side of the ramp, in the "beam" region, an unstable electron beam is seen for roughly another 10 Debye lengths along B. The electron beam is rapidly stabilized by intense electrostatic waves and nonlinear structures interpreted as electron phase-space holes. The "wave" region is physically separated from the ramp by the beam region. Numerical simulations reproduce a similar ramp structure, beam region, electrostatic turbulence region and plasma characteristics as seen in the observations. These results suggest that large double layers can account for the parallel electric field in the downward current region and that intense electrostatic turbulence rapidly stabilizes the accelerated electron distributions. These results also demonstrate that parallel electric fields are directly associated with the generation of large-amplitude electron phase-space holes and plasma waves.

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