Fast pulsed hollow cathode discharges - Time and space dependence ofbreakdown and the influence of an axial magnetic field

1987 ◽  
Author(s):  
G. SCHAEFER ◽  
K. SCHOENBACH
Keyword(s):  
Magnetic Field ◽  
Hollow Cathode ◽  
Axial Magnetic Field ◽  
Time And Space ◽  
Space Dependence

Resistive MHD modes in hollow cathodes external plasma

2021 ◽  
Author(s):  
Giulia Becatti ◽  
Francesco Burgalassi ◽  
Fabrizio Paganucci ◽  
Matteo Zuin ◽  
Dan M Goebel
Keyword(s):  
Magnetic Field ◽  
Hollow Cathode ◽  
Electric Propulsion ◽  
Axial Magnetic Field ◽  
Mhd Equations ◽  
Linear Perturbation ◽  
Plasma Parameters ◽  
Hollow Cathodes ◽  
Plume Region ◽  
Helical Mode

Abstract A significant number of plasma instabilities occur in the region just outside of hollow cathodes, depending on the injected gas flow, the current level and the application of an external magnetic field. In particular, the presence of an axial magnetic field induces a helical mode, affecting all the plasma parameters and the total current transported by the plasma. To explore the onset and behavior of this helical mode, the fluctuations in the plasma parameters in the current-carrying plume outside of a hollow cathode discharge have been investigated. The hollow cathode was operated at a current of 25 A, and at variable levels of propellant flow rate and applied magnetic fields. Electromagnetic probes were used to measure the electromagnetic fluctuations, and correlation analysis between each of the probe signals provided spatial-temporal characterization of the generated waves. Time-averaged plasma parameters, such as plasma potential and ion energy distribution function, were also collected in the near-cathode plume region by means of scanning emissive probe and retarding potential analyzer. The results show that the helical mode exists in the cathode plume at sufficiently high applied magnetic field, and is characterized by the presence of a finite electromagnetic component in the axial direction, detectable at discharge currents $\geq$ 25 A. A theoretical analysis of this mode reveals that one possible explanation is consistent with the hypotheses of resistive magnetohydrodynamics, which predicts the presence of helical modes in the forms of resistive kink. The analysis has been carried out by linear perturbation of the resistive MHD equations, from which it is possible to obtain the dispersion relation of the mode and find the $k-\omega$ unstable branch associated with the instability. These findings provided the basis for more detailed investigation of resistive MHD modes and their effect in the plume of hollow cathodes developed for electric propulsion application.

Characterization of hollow cathode vacuum arc with axial magnetic field as a concentrated heat source

Vacuum ◽  
2019 ◽  
Vol 160 ◽  
pp. 70-74 ◽  
Author(s):  
Jianping Xu ◽  
Xiubo Tian ◽  
Haiqun Qi ◽  
Jiajie Wang ◽  
Chunzhi Gong ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Heat Source ◽  
Hollow Cathode ◽  
Axial Magnetic Field ◽  
Vacuum Arc

He-Cd hollow-cathode oscillations in an axial magnetic field

1979 ◽  
Vol 12 (6) ◽  
pp. 845-851 ◽  
Author(s):  
C P Cristescu ◽  
I M Popescu ◽  
A M Preda
Keyword(s):  
Magnetic Field ◽  
Hollow Cathode ◽  
Axial Magnetic Field

Radial Emission Profiles for a Hollow Cathode Glow Discharge in an Axial Magnetic Field

1989 ◽  
Vol 43 (1) ◽  
pp. 141-148 ◽  
Author(s):  
Regis Simonneau ◽  
Richard Sacks
Keyword(s):  
Magnetic Field ◽  
Hollow Cathode ◽  
Neutral Atom ◽  
Permanent Magnets ◽  
Cathode Surface ◽  
Axial Magnetic Field ◽  
Cathode Plasma ◽  
Spatially Resolved ◽  
The Magnetic Field ◽  
The Continuum

Spatially resolved emission measurements are used to characterize the changes in plasma structure resulting from the application of an external magnetic field to an Ar hollow cathode plasma. The field is generated by ring-shaped permanent magnets which are coaxial with the cathode. The magnetic field is normal to the cathode surface and thus forms electron traps which reduce the rate of electron transport normal to the cathode surface. At lower lamp pressure, the magnetic field dramatically changes the spatial distribution of the continuum background and Ar ion radiation. Radiation from neutral-atom cathode material also is affected by the field. The magnetic field has less influence at higher pressure where collisional effects are larger.

EXPANSION OF LASER-PRODUCED ION BEAMS IN AN AXIAL MAGNETIC FIELD

2002 ◽  
Vol 6 (4) ◽  
pp. 8
Author(s):  
J. Wolowski ◽  
J. Badziak ◽  
P. Parys ◽  
E. Woryna ◽  
J. Krasa ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Axial Magnetic Field ◽  
Ion Beams

A Slotless PM Variable Reluctance Resolver with Axial Magnetic Field

2021 ◽  
pp. 1-1
Author(s):  
Le Sun ◽  
Zhejun Luo ◽  
Jun Hang ◽  
Shichuan Ding ◽  
Wei Wang
Keyword(s):  
Magnetic Field ◽  
Axial Magnetic Field ◽  
Variable Reluctance
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