新型全腔输出半透明阴极相对论磁控管的理论和数值研究
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摘要
为减小器件的体积和重量,提高器件的实用性,在轴向渐变输出结构半透明阴极相对论磁控管的基础上,提出了全腔耦合输出结构半透明阴极相对论磁控管,并对其进行了理论分析和数值模拟.采用全腔输出结构后,器件互作用区径向半径由10.5 cm降到6.6 cm,轴向长度由大于40 cm降到小于30 cm,器件尺寸显著减小.通过对输出结构的参数优化,在注入电子束电压和电流分别约为395 kV和5.6 kA、外加磁场为4.75 k Gs(1 Gs=10~(-4)T)时,模拟在S波段获得了效率约50%的微波输出,输出功率达到1.15 GW,模式更加纯净.同时还分析了耦合孔的长度、宽度和深度以及输出波导的宽度和短路面起始位置等参数对输出性能的影响规律.
Relativistic magnetron is a kind of compact cross-?eld high power microwave source.It has the virtues of wide frequency tunability and ability to operate with relative lower external magnetic ?eld.To improve the compactness and reduce the size and weight of the relativistic magnetron further,a novel relativistic magnetron using all-cavity output and semi-transparent cathode is investigated theoretically and numerically.By using the all-cavity output structure,the radial dimension is reduced markedly(from 10.5 cm to 6.6 cm) and the axial dimension is also shortened considerably(from larger than 40 cm to less than 30 cm).Since the radiation ?elds in the interaction cavity are coupled through the coupling hole to the output fan waveguide,the cutoff frequencies of the fundamental mode and three higher order modes in the fan waveguide with different outer radii are calculated.The calculation results show that the mode separation is wide enough for the single mode operation on the fundamental mode.And by using the semi-transparent cathode,the high output e?ciency can be obtained and the output characteristics are insensitive to the depth and width of each cathode slot.To verify the characteristic of the proposed magnetron,numerical simulations are carried out by using the three-dimensional particle-in-cell code.After careful optimization,simulations show that with a beam voltage of 395 kV and beam current of 5.6 k A,1.15 GW output microwave with an e?ciency of about 50% can be obtained at S-band with purer mode.The corresponding applied magnetic ?eld is 4.75 k Gs(1 Gs=10-4T).In a relatively large range,both radiation power and the optimal magnetic ?eld increase with the beam voltage.But the output e?ciency keeps almost unchanged.The effects of the depth,width and length of the coupling hole,width of the fan waveguide α and the distance from the beginning position of the fan waveguide to the coupling hole center Lsc on the output characteristics are also analyzed.Simulation results show that when the dimension of the coupling hole is small,the output power is low.But there is no mode competition and the device works on the π mode.With the increase of the coupling hole,the output power increases accordingly.When the coupling hole is large enough,the mode competition between the π mode andπ/3 mode becomes so serious that the π mode cannot win any more.At the same time,the output power decreases markedly.There also exist optimal values of both the fan width α and the beginning position of the fan waveguide(L_(sc))for maximal output power.
Relativistic magnetron is a kind of compact cross-?eld high power microwave source.It has the virtues of wide frequency tunability and ability to operate with relative lower external magnetic ?eld.To improve the compactness and reduce the size and weight of the relativistic magnetron further,a novel relativistic magnetron using all-cavity output and semi-transparent cathode is investigated theoretically and numerically.By using the all-cavity output structure,the radial dimension is reduced markedly(from 10.5 cm to 6.6 cm) and the axial dimension is also shortened considerably(from larger than 40 cm to less than 30 cm).Since the radiation ?elds in the interaction cavity are coupled through the coupling hole to the output fan waveguide,the cutoff frequencies of the fundamental mode and three higher order modes in the fan waveguide with different outer radii are calculated.The calculation results show that the mode separation is wide enough for the single mode operation on the fundamental mode.And by using the semi-transparent cathode,the high output e?ciency can be obtained and the output characteristics are insensitive to the depth and width of each cathode slot.To verify the characteristic of the proposed magnetron,numerical simulations are carried out by using the three-dimensional particle-in-cell code.After careful optimization,simulations show that with a beam voltage of 395 kV and beam current of 5.6 k A,1.15 GW output microwave with an e?ciency of about 50% can be obtained at S-band with purer mode.The corresponding applied magnetic ?eld is 4.75 k Gs(1 Gs=10-4T).In a relatively large range,both radiation power and the optimal magnetic ?eld increase with the beam voltage.But the output e?ciency keeps almost unchanged.The effects of the depth,width and length of the coupling hole,width of the fan waveguide α and the distance from the beginning position of the fan waveguide to the coupling hole center Lsc on the output characteristics are also analyzed.Simulation results show that when the dimension of the coupling hole is small,the output power is low.But there is no mode competition and the device works on the π mode.With the increase of the coupling hole,the output power increases accordingly.When the coupling hole is large enough,the mode competition between the π mode andπ/3 mode becomes so serious that the π mode cannot win any more.At the same time,the output power decreases markedly.There also exist optimal values of both the fan width α and the beginning position of the fan waveguide(L_(sc))for maximal output power.
引文
[1]Barker R J,Schamiloglu E 2001 High-Power Microwav Sources and Technologies(New York:Institute of Elec trical and Electronics Engineer,Inc.)pp56-60
[2]Liu M Q,Liu C L,Galbreath D,Michel C,Prasad SFuks M I,Schamiloglu E 2011 J.Appl.Phys.110 033304
[3]Kim H J,Choi J J 2007 IEEE Trans.Dielectr.Elect Insul.14 1045
[4]Bosman H L,Fuks M I,Prasad S,Schamiloglu E 2006IEEE Trans.Plas.Sci.34 606
[5]Fuks M I,Schamiloglu E 2010 IEEE Trans.Plas.Sci38 1302
[6]Jones M C,Neculaes V B,Lau Y Y,Gilgenbach R MWhite W M,Hoff B W,Jordan N M 2005 Appl.Phys Lett.87 081501
[7]Fuks M I,Schamiloglu E 2005 Phys.Rev.Lett.95205101
[8]Daimon M,Jiang W 2007 Appl.Phys.Lett.91 191503
[9]Hoff B W,Greenwood A D,Mardahl P J,M D Haworth2012 IEEE Trans.Plas.Sci.40 3046
[10]Fleming T P,Mardahl P J,Bowers L A,Cartwright KL 2006 Conference Record of the 2006 Twenty-Seventh International Power Modulator Symposium Arlington Virginia,USA,May 14-18,2006 p401
[11]Prasad S,Roybal M,Buchenauer C J,Prestwich K,Fuk M I,Schamiloglu E 2009 IEEE Pulsed Power Confer ence Washington,DC,USA,June 27-July 1,2009 p81
[12]Yamazaki H,Jiang W 2007 Proceedings of ITC/ISHWToki,Japan,October 15-19,2007 p1
[13]Su L,Li T M,Li J Y 2011 High Power Laser and Par ticle Beams 23 3039(in Chinese)[苏黎,李天明,李家胤2011强激光与粒子束23 3039]
[14]Li W,Liu Y,Zhang J,Shu T,Yang H,Fan Y,Yuan C2012 Rev.Sci.Instrum.83 024707
[15]Yang W,Dong,Z,Yang Y,Dong Y 2014 IEEE Trans Plas.Sci.42 3458
[16]Greenwood A D 2006 US Patent 7 106 004[2006-9-12]
[17]Zhang K Q,Li D J 2001 Electromagnetic Theory in Mi crowaves and Optoelectronics(1st Ed.)(Beijing:Pub lishing House of Electronics Industry)pp295-297(in Chinese)[张克潜,李德杰2001微波与光电子学中的电磁理论(第1版)(北京:电子工业出版社)第295-297页]
[2]Liu M Q,Liu C L,Galbreath D,Michel C,Prasad SFuks M I,Schamiloglu E 2011 J.Appl.Phys.110 033304
[3]Kim H J,Choi J J 2007 IEEE Trans.Dielectr.Elect Insul.14 1045
[4]Bosman H L,Fuks M I,Prasad S,Schamiloglu E 2006IEEE Trans.Plas.Sci.34 606
[5]Fuks M I,Schamiloglu E 2010 IEEE Trans.Plas.Sci38 1302
[6]Jones M C,Neculaes V B,Lau Y Y,Gilgenbach R MWhite W M,Hoff B W,Jordan N M 2005 Appl.Phys Lett.87 081501
[7]Fuks M I,Schamiloglu E 2005 Phys.Rev.Lett.95205101
[8]Daimon M,Jiang W 2007 Appl.Phys.Lett.91 191503
[9]Hoff B W,Greenwood A D,Mardahl P J,M D Haworth2012 IEEE Trans.Plas.Sci.40 3046
[10]Fleming T P,Mardahl P J,Bowers L A,Cartwright KL 2006 Conference Record of the 2006 Twenty-Seventh International Power Modulator Symposium Arlington Virginia,USA,May 14-18,2006 p401
[11]Prasad S,Roybal M,Buchenauer C J,Prestwich K,Fuk M I,Schamiloglu E 2009 IEEE Pulsed Power Confer ence Washington,DC,USA,June 27-July 1,2009 p81
[12]Yamazaki H,Jiang W 2007 Proceedings of ITC/ISHWToki,Japan,October 15-19,2007 p1
[13]Su L,Li T M,Li J Y 2011 High Power Laser and Par ticle Beams 23 3039(in Chinese)[苏黎,李天明,李家胤2011强激光与粒子束23 3039]
[14]Li W,Liu Y,Zhang J,Shu T,Yang H,Fan Y,Yuan C2012 Rev.Sci.Instrum.83 024707
[15]Yang W,Dong,Z,Yang Y,Dong Y 2014 IEEE Trans Plas.Sci.42 3458
[16]Greenwood A D 2006 US Patent 7 106 004[2006-9-12]
[17]Zhang K Q,Li D J 2001 Electromagnetic Theory in Mi crowaves and Optoelectronics(1st Ed.)(Beijing:Pub lishing House of Electronics Industry)pp295-297(in Chinese)[张克潜,李德杰2001微波与光电子学中的电磁理论(第1版)(北京:电子工业出版社)第295-297页]