Can surface cracks and unipolar arcs explain breakdown and gradient limits?

Journal Article · Tue Jan 15 04:00:00 EST 2013 · Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films

DOI:https://doi.org/10.1116/1.4766929· OSTI ID:22099141

Insepov, Zeke; Norem, Jim ^[1]

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1. Argonne National Laboratory, Argonne, Illinois 60439 (United States)

The authors argue that the physics of unipolar arcs and surface cracks can help understand rf breakdown and vacuum arc data. They outline a model of the basic mechanisms involved in breakdown and explore how the physics of unipolar arcs and cracks can simplify the picture of breakdown and gradient limits in accelerators, tokamaks as well as laser ablation, micrometeorites, and other applications. Cracks are commonly seen in SEM images of arc damage and they are produced as the liquid metal cools. They can produce the required field enhancements to explain field emission data and can produce mechanical failure of the surface that would trigger breakdown events. Unipolar arcs can produce currents sufficient to short out rf structures, and can cause the sort of damage seen in SEM images. They should be unstable, and possibly self-quenching, as seen in optical fluctuations and surface damage. The authors describe some details and consider the predictions of this simple model.

• OSTI ID: 22099141
• Journal Information: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films, Journal Name: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films Journal Issue: 1 Vol. 31; ISSN 0734-2101; ISSN JVTAD6
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ABLATION
ACCELERATORS
BREAKDOWN
CRACKS
FIELD EMISSION
FLUCTUATIONS
HIGH-FREQUENCY DISCHARGES
LASER RADIATION
LIQUID METALS
QUENCHING
RF SYSTEMS
SCANNING ELECTRON MICROSCOPY
SURFACES
TOKAMAK DEVICES