Multidimensional short-pulse space-charge-limited flow
- School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore)
The two-dimensional models of the space-charge-limited (SCL) current density at the short pulse limit for which the electron pulse length is comparable or smaller than the electron transit time across the gap (i.e., X{sub CL}{<=}1) have been developed. In particular, the scaling laws for short-pulse SCL electron emission in a planar diode with a circular emitting strip and a cylindrical diode with a finite length have been obtained and verified with particle-in-cell simulation. It is found that the enhancement (in terms of the long-pulse SCL current density) is proportional to X{sub CL}{sup -1} for small X{sub CL} for both planar and cylindrical cases. The enhancement of the cylindrical short-pulse SCL current density is also found to be larger for the convergent flow (cathode outside) than divergent flow (cathode inside). Multidimensional effects are important only for small emitting strips with size comparable to the effective penetration distance (into the gap) of the short-pulse electron beam. Smooth transition between the short-pulse regime and the long pulse (steady-state) regime is demonstrated.
- OSTI ID:
- 20787385
- Journal Information:
- Physics of Plasmas, Vol. 13, Issue 6; Other Information: DOI: 10.1063/1.2208086; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Effects of emitting surfaces and trapped ions on the sheath physics and current flow in multidimensional plasma systems
Short-pulse space-charge-limited electron flows in a drift space
Related Subjects
BEAM-PLASMA SYSTEMS
CATHODES
CURRENT DENSITY
CYLINDRICAL CONFIGURATION
ELECTRON BEAMS
ELECTRON EMISSION
ELECTRONS
PLASMA
PLASMA SIMULATION
PULSES
RADIATION TRANSPORT
SCALING LAWS
SPACE CHARGE
STEADY-STATE CONDITIONS
THERMIONIC DIODES
TWO-DIMENSIONAL CALCULATIONS