## Abstract

A low-density plasma flow in a vacuum arc with a small anode which intercepts only part of the cathodic plasma was studied theoretically using a two-dimensional approximation. The plasma expansion was modeled using the sourceless steady-state hydrodynamic equations, where the free boundary of the plasma was determined by a self-consistent solution of the gas-dynamic and electrical current equations. The influence of the ratio of the anode radius R_{a} to initial plasma jet radius R_{o} on the plasma density, velocity, current distribution and anode sheath voltage drop is analyzed. The mass and current flow in a 500 A arc with R_{a}/R_{o} = 1 are compressed near the axis, leading to an increase in the plasma density by a factor of 2 and in the axial current density by a factor of 1.5 at a distance of about the plasma jet radius from the starting plane. In this case the radial anode sheath drop distribution is approximately uniform and the anode sheath drop has a value of about 0.4 T_{e} where T_{e} is the electron temperature. In the case of a small anode, the anode sheath potential drop becomes non-uniform radially and the centerline anode voltage drop increases to 0.9 T_{e}.

Original language | English |
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Pages | 232-235 |

Number of pages | 4 |

State | Published - 1998 |

Event | Proceedings of the 1998 18th Interantional Symposium on Discharges and Electrical Insulation in Vacuum. Part 1 (of 2) - Eindhoven, Neth Duration: 17 Aug 1998 → 21 Aug 1998 |

### Conference

Conference | Proceedings of the 1998 18th Interantional Symposium on Discharges and Electrical Insulation in Vacuum. Part 1 (of 2) |
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City | Eindhoven, Neth |

Period | 17/08/98 → 21/08/98 |