脈沖磁控管的陰極問題
CATHODE PROBLEM IN PULSED MAGNETRONS
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摘要: 在脈沖磁控管中,陽極電流可以用兩個不同的公式表示。一是屬于具體管型的,包含電磁參數(shù)和管的幾何尺寸,它描述陽極如何從切向迴旋的電子云中提取電子。另一個只與陰極的熱發(fā)射、回轟系數(shù)和次級發(fā)射系數(shù)有關(guān),它描述陰極向迴旋電子云供應(yīng)電子的一般方式。二者有緊密的聯(lián)系,但又是不同的物理過程。我們將這兩個公式和互作用空間中的電子云運(yùn)動結(jié)合起來,便能更好地了解磁控管的工作機(jī)制。 為了使磁控管能穩(wěn)定工作,就要使預(yù)振電壓低于門檻電壓,并且使空間電荷振蕩的模式與諧振腔上高頻振蕩的模同步。在起振之后,陽極電流應(yīng)近似地由次級發(fā)射供應(yīng),而回轟電流則近似地由熱發(fā)射供應(yīng)。此條件能保證得到較好的工作狀態(tài)。
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關(guān)鍵詞:
Abstract: There are two different expressions for anode current of pulsed magnetrons. The one. comprising electric and magnetic parameters as well as tube geometries, describes how the electrons are picked up from the rotating electron stream near anode space; the other, stating the relation between thermal emission, coefficient of back bombardment and coefficient of secondary emission, is a general description of supplying electrons to the rotating stream by the ca-thode without concern to a particular tube. Each of the above expressions has its own physical significance while they are closely connected to each other through the rotaing eectron stream. The integration of these expressions with the electron motions in the interaction space leads to better understanding of the mechanism of magnetrons. For stable operation of the magnetron, the preoscillation voltage should be lower than the threshold voltage, while the mode of this space charge oscillation should be the same as the mode oscillation on the resonating cavities. After starting of the resonance, that the thermal emission approximately equals the back bombarding current and the secondary emission approximately equals the anode current respectively exhibits condition of good performance. -
S. P. Yu, G. P. Kooyers and O. Buneman, J. Appl. Phys., 36(1965), 2550.[2]磁控管設(shè)計(jì)手冊,國防工業(yè)出版社,(1979), 34頁.[3]T. J. Orzechowski and G. Bekefi, Phys. Fluids, 22(1979), 978.[4]A. Palevsky and G. Bekefi, ibid, 22(1979), 986.[5]W. C. Brown, IEEE Trans. on ED, ED-31(1984), 1595.[6]E. Q. Zhang, ibid., ED-24(1980), 1280.[7]J. F. Hull, IRE Trans. on ED, ED-8(1961), 309.[8]J. R. M. Vaughan, IEEE Trans. on ED, ED-20(1973), 818.[9]張恩虬,電子管技術(shù),1977年,第6期,第90頁.[10]張恩虬,科學(xué)通報(bào),1976年,第6期,第252頁.[11]E. Okress, Crossed-Field Microwave Devices, Vol. 1,(1961), Academic Press, New York and London.[12]張恩虬,電子學(xué)通訊,1(1979), 1.[13]D. Barker, An Experimental Investigation of the Energy Distribution of Returning Electrons in Magnetron, 8th Int. Conf. Microwave and Optical Generation and Amplification, The Netherlands: Kluwer-Deventer, (1970), 8-7.[14]J. R. M. Vaughan, IEEE Trans. on ED, ED-15(1968), 883.[15]E. Q. Zhang, ibid., ED-33(1986), 1383.[16]賈學(xué)標(biāo),關(guān)于磁控管陰極發(fā)射與振蕩建立問題的討論兼論同軸磁控管的前沿抖動問題,真空電子學(xué)第六屆學(xué)術(shù)年會論文摘要匯編,北京,1986, 42 -
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