Bölgesel magnetik alanlı bir demet plazma sisteminde karakteristik frekanslara yakın etkileşmeler
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Date
1973-11
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T.C. Atom Enerjisi Komisyonu, Ankara Nükleer Araştırma Merkezi
Abstract
Magnetron enjeksiyonlu bir elektron topuna 8.10(-4) Torr bir baskı sınırı olmak üzere, hrdrojen gazı verildiği zaman, magnetostatic ve elektrostatic mercekler içinde demet-plazma boşalması meydana gelmektedir. Elektron demeti ile, bu demetin oluşturduğu plazma birbirlerini etkilemektedir. Etkileşme sırasında toplam plazma, elektron siklotron ve iyon siklotron gibi karakteristik frekanslara yakın bası dalga rezonansları ortaya çıkmaktadır.
Bu çalışmada I(D) elektron demet akımı, p sistemin gaz baskısı ve Bz magnetron bobinindeki alan şiddeti değiştirilmek suretiyle bu rezonanslar analizlermiş ve sonuçlar tartışılmıştır.
Magnetron enjeksiyonunu sağlayan bölgesel magnetostatik alanın aynı zamanda magnetostatik mercek Özelliği göz önünde tutulursa merceğin temel düzlemlerini dikkate almak gerekmektedir. Bunların yerleri bobin merkezinden yaklaşık olarak 7 cm uzaklıktadır. Bu düzlemler demet-plazma boşalmasını etkilemektedir. Başka deyişle, bu noktaya kadar eksene paralel bir demet halinde gelen elektronlar, temel düzlemde kırılarak konik bir demet biçimine dönüşmektedir. Magnetostatik bir sistemde plazmanın ısınması, taneciklerin hız vektörü ile magnetik alanın kuvvet çizgileri arasında bir 0 açısının meydana gelmesiyle mümkün olduğuna göre, plazmanın magnetostatik merceğin temel düzleminden geçtikten sonra ısınmaya başladığı söylenebilir, öte yandan spektrum analizöründe saptanan elektron siklotron frekansına ait etkileşme rezonansının alan değerinin, bobin merkezinden 7 cm uzaklıktaki alan değerine eşit olduğu görülmüştür. Böylece etkileşmenin bu bölgede plazma ısınırken başlıyacağı kabul edilebilir. Bundan başka, iyon siklotron frekansına yakın etkileşmenin, iyon siklotron frekansından biraz büyük olduğu görülmüştür. Elde edilen plazma ılık olduğuna göre, dispersiyon denkleminde temperatur terim korunarak bu oluş da açıklığa kavuşturulmuştur.
When hydrogen gas is supplied within 8,10 Torr. pressure limit to a magnetron injection electron gun, a beam-plasma discharge occurs within the magnetostatic and electrostatic lenses. The electron beam and the plasma created by the beam interact with each other. In the course of this interaction, certain wave resonnances occur at frequencies approximating such characteristic frequencies as those of the total plasma the electron cyclotron and the ion cyclotron. In this study, the said resonnances were analysed under controlled variations in the electron beam current (ID) gas pressure of the system (p) and in field intensity of the magnetron coil (Bz) and the results are discussed. In consideration of the magnetostatic lens properties of the magnetostatic field which produces magnetron injeexion it is obivous that the principal planes of the lens should receive due attention. The principal planes are situated approximately 7 cm. away from the coil center. These planes affect beam-plasma discharges, In other words, electrons which travel in the from of a beam prallel to the axis of the system up to this point are refracted by the principel plane and converted to a conical beam. Inasmuch as the heating of the plasma in a magnetostatic system is contingent upen formation of a 0 angle betweel the velocity vector of the particles and the force lines of the magnetic field it can be derived that heating of the plasma commences after passing through the pincipal plane of the magnetostatic lens. Furthermore, it was observed that the field intensity value of the interaction resonnance corresponding to the electron cyclotron frequency as determined with the spectrum analyzer was equal to the field intensity at a distance of 7 era. from the center of the coil. It can he therefore assumed that interaction would begin as heating of plasma commences in this zone. It was further observed that interaction close to the ion cyclotron frequency was at a frequency slightly higher then that of the ion cyclotron. Inasmuch as the plasma obtained is worm, this occurrence becomes explicit by maintaining the temperature term in the dispersion equation.
When hydrogen gas is supplied within 8,10 Torr. pressure limit to a magnetron injection electron gun, a beam-plasma discharge occurs within the magnetostatic and electrostatic lenses. The electron beam and the plasma created by the beam interact with each other. In the course of this interaction, certain wave resonnances occur at frequencies approximating such characteristic frequencies as those of the total plasma the electron cyclotron and the ion cyclotron. In this study, the said resonnances were analysed under controlled variations in the electron beam current (ID) gas pressure of the system (p) and in field intensity of the magnetron coil (Bz) and the results are discussed. In consideration of the magnetostatic lens properties of the magnetostatic field which produces magnetron injeexion it is obivous that the principal planes of the lens should receive due attention. The principal planes are situated approximately 7 cm. away from the coil center. These planes affect beam-plasma discharges, In other words, electrons which travel in the from of a beam prallel to the axis of the system up to this point are refracted by the principel plane and converted to a conical beam. Inasmuch as the heating of the plasma in a magnetostatic system is contingent upen formation of a 0 angle betweel the velocity vector of the particles and the force lines of the magnetic field it can be derived that heating of the plasma commences after passing through the pincipal plane of the magnetostatic lens. Furthermore, it was observed that the field intensity value of the interaction resonnance corresponding to the electron cyclotron frequency as determined with the spectrum analyzer was equal to the field intensity at a distance of 7 era. from the center of the coil. It can he therefore assumed that interaction would begin as heating of plasma commences in this zone. It was further observed that interaction close to the ion cyclotron frequency was at a frequency slightly higher then that of the ion cyclotron. Inasmuch as the plasma obtained is worm, this occurrence becomes explicit by maintaining the temperature term in the dispersion equation.
Description
TENMAK D.N.. 8284
Keywords
Electrons, Elektronlar
Citation
Sinman, A. ve Sinman, S. (1973). Bölgesel magnetik alanlı bir demet plazma sisteminde karakteristik frekanslara yakın etkileşmeler. Ankara : T.C. Atom Enerjisi Komisyonu, Ankara Nükleer Araştırma Merkezi.