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Deng Y.,Shaanxi Power Machine Design and Research Institute | Tan C.,Shaanxi Power Machine Design and Research Institute | Han X.,Shaanxi Power Machine Design and Research Institute | Tan Y.,China Aerospace Science and Technology Corporation
Plasma Science and Technology | Year: 2012

For exploiting advantages of electron beam air plasma in some unusual applications, a Monte Carlo (MC) model coupled with heat transfer model is established to simulate the characteristics of electron beam air plasma by considering the self-heating effect. Based on the model, the electron beam induced temperature field and the related plasma properties are investigated. The results indicate that a nonuniform temperature field is formed in the electron beam plasma region and the average temperature is of the order of 600 K. Moreover, much larger volume pear-shaped electron beam plasma is produced in hot state rather than in cold state. The beam ranges can, with beam energies of 75 keV and 80 keV, exceed 1.0 m and 1.2 m in air at pressure of 100 torr, respectively. Finally, a well verified formula is obtained for calculating the range of high energy electron beam in atmosphere.


Deng Y.,Shaanxi Power Machine Design and Research Institute | Tan Y.,China Aerospace Science and Technology Corporation | Han X.,Shaanxi Power Machine Design and Research Institute
Physics of Plasmas | Year: 2014

Using high-energy electron beams to ionize air is an effective way to produce a large-size plasma in the atmosphere. In particular, with a steady-state high power generator, some unique phenomena can be achieved, including natural convection of the plasma. The characteristics of this convection are studied both experimentally and numerically. The results show that an asymmetrical temperature field develops with magnitudes that vary from 295K to 389K at a pressure of 100Torr. Natural convection is greatly enhanced under 760Torr. Nevertheless, plasma transport is negligible in this convection flow field and only the plasma core tends to move upward. Parameter analysis is performed to discern influencing factors on this phenomenon. The beam current, reflecting the Rayleigh number Ra effect, correlates with convection intensity, which indicates that energy deposition is the underlying key factor in determining such convections. Finally, natural convection is concluded to be an intrinsic property of the electron beam when focused into dense air, and can be achieved by carefully adjusting equipment operations parameters. © 2014 AIP Publishing LLC.


Deng Y.,Shaanxi Power Machine Design and Research Institute | Tan Y.,China Aerospace Science and Technology Corporation | Han X.,Shaanxi Power Machine Design and Research Institute
Plasma Science and Technology | Year: 2014

Large size of air plasma at near atmospheric pressure has specific effects in aerospace applications. In this paper, a two dimensional multi-fluid model coupled with Monte Carlo (MC) model is established, and some experiments were carried out to investigate the characteristics of electron beam air plasma at pressure of 100-170 Torr. Based on the model, the properties of electron beam air plasma are acquired. The electron density is of the order of 1016 m-3 and the longitudinal size can exceed 1.2 m. The profiles of charged particles demonstrate that the oxygen molecule is very important for air plasma and its elementary processes play a key role in plasma equilibrium processes. The potential is almost negative and a very low potential belt is observed at the edge of plasma acting as a protection shell. A series of experiments were carried out in a low pressure vacuum facility and the beam plasma densities were diagnosed. The experimental results demonstrate that electron density increased with the electron beam energy, and the relatively low pressure was favorable for gaining high density plasma. Hence in order to achieve high density and large size plasma, it requires the researchers to choose proper discharge parameters.


Luan X.,Northwestern Polytechnical University | Deng Y.,Shaanxi Power Machine Design and Research Institute | Tan C.,Shaanxi Power Machine Design and Research Institute | Han X.,Shaanxi Power Machine Design and Research Institute | Mao G.,Northwestern Polytechnical University
He Jishu/Nuclear Techniques | Year: 2010

Based on Geant4 Monte Carlo toolkit, a numerical model is established to simulate the electron beam transportation characteristics under low-vacuum condition. The results indicate that the low-vacuum transportation characteristics differ greatly from the high-vacuum case. The residual gas affects the beam trajectory greatly, but the magnetic field can focus the beam effectively. The final trajectory is determined by both effects. For a given magnetic field, in order to get the desired beam, the beam energy should be in a reasonable range.


Luan X.,Northwestern Polytechnical University | Deng Y.,Shaanxi Power Machine Design and Research Institute | Tan C.,Shaanxi Power Machine Design and Research Institute | Han X.,Shaanxi Power Machine Design and Research Institute | Mao G.,Northwestern Polytechnical University
Qiangjiguang Yu Lizishu/High Power Laser and Particle Beams | Year: 2010

The atmospheric electron-beam produced air plasma attracts intensive attentions recently. Based on a Monte Carlo toolkit named Geant4, a model including complete physics processes is established to simulate the passage of the electron beam in air in nonuniform magnetic field. By using the model, the characteristics of the electron-beam produced air plasma are simulated. The results indicate that, the nonuniform magnetic field is effective controlling the trajectories of electron beams and can reduce the beam divergence obviously. The energy spectrum becomes wider with the increase of beam penetration depth and secondary electrons play a significant role in low energy range. Moreover, the magnitude of energy deposition at the outlet of the transportation section is two orders higher than that at the beam end, and the highest plasma density appears at the outlet. Thus, a conclusion is drawn that the plasma density is closely related to the beam energy.

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