Stability of a self-gravitating homogeneous spheroid with azimuthal magnetic field. II

Astrophysics ◽  
1990 ◽  
Vol 30 (3) ◽  
pp. 395-399
Author(s):  
V. A. Antonov ◽  
O. A. Zheleznyak
Keyword(s):  
Magnetic Field ◽  
Azimuthal Magnetic Field ◽  
Homogeneous Spheroid

scholarly journals New possibilities of collectors with azimuthal magnetic field for multistage energy recovery in gyrotrons

2021 ◽  
Vol 2103 (1) ◽  
pp. 012058
Author(s):  
I Louksha ◽  
P A Trofimov ◽  
B D Usherenko
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Energy Recovery ◽  
Trajectory Analysis ◽  
Spatial Separation ◽  
Total Efficiency ◽  
Optimal Parameters ◽  
Azimuthal Magnetic Field ◽  
Electron Trajectories ◽  
Collector Region

Abstract The results of modeling a collector with 4-stage recovery of residual electron energy for the SPbPU gyrotron with a frequency of 74.2 GHz and an output power of 100 kW are presented. For spatial separation of electrons with different energies, an azimuthal magnetic field created by a toroidal solenoid is used. An increase of the recovery efficiency and a decrease of the current of electrons reflected from the collector is achieved by reducing the spread of the radial position of the leading centers of electron trajectories at optimal parameters of the toroidal solenoid, as well as by using a sectioned electron beam. The trajectory analysis of the spent electron beam in the collector region showed the possibility of achieving the total efficiency of the gyrotron, close to 80%.

Helical Magnetic Cavities: Kinetic Model and Comparison with MMS Observations

2021 ◽  
Author(s):  
Jinghuan Li ◽  
Xuzhi Zhou ◽  
Fan Yang ◽  
Anton V. Artemyev ◽  
Qiugang Zong
Keyword(s):  
Magnetic Field ◽  
Kinetic Model ◽  
Pitch Angle ◽  
Maxwell Equations ◽  
Equilibrium Solution ◽  
Space Plasma ◽  
Azimuthal Magnetic Field ◽  
Particle Distributions ◽  
Multi Scale ◽  
Self Consistent

<p>Magnetic cavities are sudden depressions of magnetic field strength widely observed in the space plasma environments, which are often accompanied by plasma density and pressure enhancement. To describe these cavities, a self-consistent kinetic model has been proposed as an equilibrium solution to the Vlasov-Maxwell equations. However, observations from the Magnetospheric Multi-Scale (MMS) constellation have shown the existence of helical magnetic cavities characterized by the presence of azimuthal magnetic field, which could not be reconstructed by the aforementioned model. Here, we take into account another invariant of motion, the canonical axial momentum, to construct the particle distributions and accordingly modify the equilibrium model. The reconstructed magnetic cavity shows excellent agreement with the MMS1 observations not only in the electromagnetic field and plasma moment profiles but also in electron pitch-angle distributions. With the same set of parameters, the model also predicts signatures of the neighboring MMS3 spacecraft, matching its observations satisfactorily.</p>

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