Enhancement of electro dynamic tether electron current collection using radio frequency power: Numerical modeling and measurements

Éric Choinière, Brian E. Gilchrist, Sven G. Bilén

Research output: Contribution to conferencePaper

Abstract

Tether electron current collection in the Orbital Motion Limited regime is one of the limiting factors in power and thrust generation applications of electro dynamic tethers. Injection of radio frequency power along tethers is considered in order to enhance electron current collection. As a basic assessment tool, Particle-In-Cell modeling of the tether system is performed using a 1-d cylindrical code. Comparison of test electron trajectories shows that the time periodic field distribution created by the RF excitation results in electrons being scattered off their usual OML trajectories, which under some conditions increases their probability of being collected by the tether. Analysis of simulation results reveals that large current enhancements can occur at resonance frequencies of the input reactance (where Xin = 0), but at the expense of high RF power. Current enhancement is best measured in terms of the relative current variation per unit of RF power dissipated for every 1-meter section of the tether. Optimum enhancements of about 9% per RF watt per meter were obtained by simulation at low frequencies (75 MHz). Similar enhancements were observed during Phase 1 of the experimental measurements on tether samples. Initial experimental results from Phase 2 of the tests are presented in which the RF power was kept constant at a reference plane along the transmission line connecting to a tether sample. These results show some frequency dependence of the current enhancement for a fixed power level. Further measurements are needed which will control the RF power sent at the tether sample itself, rather than at an upstream position on the transmission line.

Original languageEnglish (US)
StatePublished - Dec 1 2001
Event37th Joint Propulsion Conference and Exhibit 2001 - Salt Lake City, UT, United States
Duration: Jul 8 2001Jul 11 2001

Other

Other37th Joint Propulsion Conference and Exhibit 2001
CountryUnited States
CitySalt Lake City, UT
Period7/8/017/11/01

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Electrons
Electric lines
Trajectories

All Science Journal Classification (ASJC) codes

  • Energy Engineering and Power Technology
  • Aerospace Engineering
  • Control and Systems Engineering
  • Electrical and Electronic Engineering
  • Mechanical Engineering

Cite this

Choinière, É., Gilchrist, B. E., & Bilén, S. G. (2001). Enhancement of electro dynamic tether electron current collection using radio frequency power: Numerical modeling and measurements. Paper presented at 37th Joint Propulsion Conference and Exhibit 2001, Salt Lake City, UT, United States.
Choinière, Éric ; Gilchrist, Brian E. ; Bilén, Sven G. / Enhancement of electro dynamic tether electron current collection using radio frequency power : Numerical modeling and measurements. Paper presented at 37th Joint Propulsion Conference and Exhibit 2001, Salt Lake City, UT, United States.
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Choinière, É, Gilchrist, BE & Bilén, SG 2001, 'Enhancement of electro dynamic tether electron current collection using radio frequency power: Numerical modeling and measurements', Paper presented at 37th Joint Propulsion Conference and Exhibit 2001, Salt Lake City, UT, United States, 7/8/01 - 7/11/01.

Enhancement of electro dynamic tether electron current collection using radio frequency power : Numerical modeling and measurements. / Choinière, Éric; Gilchrist, Brian E.; Bilén, Sven G.

2001. Paper presented at 37th Joint Propulsion Conference and Exhibit 2001, Salt Lake City, UT, United States.

Research output: Contribution to conferencePaper

TY - CONF

T1 - Enhancement of electro dynamic tether electron current collection using radio frequency power

T2 - Numerical modeling and measurements

AU - Choinière, Éric

AU - Gilchrist, Brian E.

AU - Bilén, Sven G.

PY - 2001/12/1

Y1 - 2001/12/1

N2 - Tether electron current collection in the Orbital Motion Limited regime is one of the limiting factors in power and thrust generation applications of electro dynamic tethers. Injection of radio frequency power along tethers is considered in order to enhance electron current collection. As a basic assessment tool, Particle-In-Cell modeling of the tether system is performed using a 1-d cylindrical code. Comparison of test electron trajectories shows that the time periodic field distribution created by the RF excitation results in electrons being scattered off their usual OML trajectories, which under some conditions increases their probability of being collected by the tether. Analysis of simulation results reveals that large current enhancements can occur at resonance frequencies of the input reactance (where Xin = 0), but at the expense of high RF power. Current enhancement is best measured in terms of the relative current variation per unit of RF power dissipated for every 1-meter section of the tether. Optimum enhancements of about 9% per RF watt per meter were obtained by simulation at low frequencies (75 MHz). Similar enhancements were observed during Phase 1 of the experimental measurements on tether samples. Initial experimental results from Phase 2 of the tests are presented in which the RF power was kept constant at a reference plane along the transmission line connecting to a tether sample. These results show some frequency dependence of the current enhancement for a fixed power level. Further measurements are needed which will control the RF power sent at the tether sample itself, rather than at an upstream position on the transmission line.

AB - Tether electron current collection in the Orbital Motion Limited regime is one of the limiting factors in power and thrust generation applications of electro dynamic tethers. Injection of radio frequency power along tethers is considered in order to enhance electron current collection. As a basic assessment tool, Particle-In-Cell modeling of the tether system is performed using a 1-d cylindrical code. Comparison of test electron trajectories shows that the time periodic field distribution created by the RF excitation results in electrons being scattered off their usual OML trajectories, which under some conditions increases their probability of being collected by the tether. Analysis of simulation results reveals that large current enhancements can occur at resonance frequencies of the input reactance (where Xin = 0), but at the expense of high RF power. Current enhancement is best measured in terms of the relative current variation per unit of RF power dissipated for every 1-meter section of the tether. Optimum enhancements of about 9% per RF watt per meter were obtained by simulation at low frequencies (75 MHz). Similar enhancements were observed during Phase 1 of the experimental measurements on tether samples. Initial experimental results from Phase 2 of the tests are presented in which the RF power was kept constant at a reference plane along the transmission line connecting to a tether sample. These results show some frequency dependence of the current enhancement for a fixed power level. Further measurements are needed which will control the RF power sent at the tether sample itself, rather than at an upstream position on the transmission line.

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Choinière É, Gilchrist BE, Bilén SG. Enhancement of electro dynamic tether electron current collection using radio frequency power: Numerical modeling and measurements. 2001. Paper presented at 37th Joint Propulsion Conference and Exhibit 2001, Salt Lake City, UT, United States.