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从空间飞行器入射进电离层的调制电子束产生的高频波辐射 总被引:2,自引:1,他引:1
在主动束-等离子体试验中,调制电子束从空间飞行器入射进电离层等离子体将会产生电磁波辐射,在不同试验条件下电磁波辐射机理也不一样,由电子束纵向约束性产生电磁波辐射是其中之一.对半无界稀薄调制电子束从空间飞行器入射进电离层等离子体时所产生的波现象进行了理论分析和数值计算.结果表明,当调制电子束沿磁力线入射时,会在电离层等离子体中产生高频电磁波辐射,该辐射主要集中在垂直于入射电子束运动方向的平面内. 相似文献
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R. L. Arnoldy L. J. Cahill Jr P. M. Kintner T. E. Moore C. J. Pollock 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1992,12(12):1-7
Data from ARCS rocket ion beam injection experiments will be primarily discussed in this paper. There are three results from this series of active experiments that are of particular interest in space plasma physics. These are the transverse acceleration of ambient ions in the large beam volume, the scattering of beam ions near the release payload, and the possible acceleration of electrons very close to the plasma generator which produce intense high frequency waves. The ability of 100 ma ion beam injections into the upper E and F regions of the ionosphere to produce these phenomena appear to be related solely to the process by which the plasma release payload and the ion beam are neutralized. Since the electrons in the plasma release do not convect with the plasma ions, the neutralization of both the payload and beam must be accomplished by large field-aligned currents (milliamperes/square meter) which are very unstable to wave growth of various modes. Future work will concentrate on the wave production and wave-particle interactions that produce the plasma/energetic particle effects discussed in this paper and which have direct application to natural phenomena in the upper ionosphere and magnetosphere. 相似文献
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S. Sasaki N. Kawashima A. Yamori T. Obayashi O. Kaneko 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1981,1(2):417-420
Simulation experiments on spacecraft charging in space plasma and its neutralization are performed in relation to the electron beam experiment (SEPAC) on Space Shuttle Spacelab 1. A spacecraft simulator or a spherical probe is immersed in a magnetized plasma and a positive high voltage with respect to the plasma is externally applied to it. The current-voltage characteristics follow quite well with the theoretical model of Parker and Murphy [1] in the low voltage, low pressure region. When the voltage rises to more than the ionization potential of the surrounding neutral gas, it departs from the model and the effect of plasma production by the electron current becomes very important. The same kind of ionization effect as this has also been observed in our rocket experiments with an electron beam. The enhancement of the ionization effect by an additional neutral gas injection causes a considerable suppression of the potential rise of a spacecraft emitting an electron beam. This is demonstrated with the SEPAC accelerators in a large space chamber experiment. 相似文献
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由于很大一部分来自激波上游的粒子被激波面所反射,因此在准平行无碰撞激波的上游存在着等离子体束流.通过一维混合模拟方法,计算了束流密度较小(nb/n0=0.02)和较大(nb/n0=0.2)两种不同情形下的等离子体束流不稳定性.结果表明,在束流密度较小时,束流激发的主要是平行于背景磁场方向传播的右旋波,此波动只能对束流粒子产生影响,包括减速和加热.在束流密度较大时,束流可同时激发平行和反平行于背景磁场方向传播的右旋波,除能对束流粒子产生影响外,还可通过非共振作用加速和加热背景粒子.文中对准平行无碰撞激波耗散机制的影响也进行了讨论。 相似文献
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考虑热束流等离子体无碰撞地通过背景等离子体时, 由等离子体系统的流体方程组出发用递减扰动法推导了描写离子声孤波的Kortewegde-Vries方程.在弱束流的条件下, 四种离子声波模式中有两种分别对应慢孤波和快孤波.计算了两种孤波振幅对等离子体参量的依赖关系, 在某些参量配合下有可能得到大振幅的正孤波和负孤波. 相似文献
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《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2023,71(4):1948-1961
In this paper the influence of large-scale decreasing and increasing gradients of the density of magnetized plasma on the relaxation process of a continuously injected relativistic electron beam with an energy of 660 keV () and a pitch-angle distribution is studied using particle-in-cell numerical simulations. It is found that for the selected parameters in the case of a smoothly decreasing gradient and in a homogeneous plasma the formation of spatially limited plasma oscillations of large amplitude occurs. In such cases, modulation instability develops and a long-wave longitudinal modulation of the ion density is formed. In addition, the large amplitude of plasma waves accelerates plasma electrons to energies on the order of the beam energy. In the case of increasing and sharply decreasing gradients, a significant decrease in the amplitude of plasma oscillations and the formation of a turbulent ion density spectrum are observed. The possibility of acceleration of beam electrons to energies more than 2 times higher than the initial energy of the beam particles is also demonstrated. This process takes place not only during beam propagation in growing plasma density, but also in homogeneous plasma due to interaction of beam particles with plasma oscillations of large amplitude. 相似文献
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等离子体密度对栅极系统束流影响分析 总被引:1,自引:0,他引:1
针对现有离子推力器栅极系统束流引出分析中未考虑放电室等离子体密度均匀性影响的不足,基于数值方法对该问题进行了研究。采用单元内粒子 (Particle In Cell,PIC) 方法对栅极系统束流引出进行了数值模拟。PIC方法中电场求解采用有限差分方法,离子加速方法采用跳蛙格式。以国产20cm Xe离子推力器作为算例,计算得到了栅极中心和边缘孔引出束流离子和电场的分布。结果显示栅极中心孔相对边缘孔束流聚焦性好,束流发散角小,但中心孔轴线的鞍点电势较边缘孔高24.8V。因此,放电室等离子体密度分布对束流引出具有重要影响,电子返流现象最先出现在栅极中心位置。 相似文献
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N. Kawashima S. Sasaki A. Ushikoshi Y. Yagi T. Obayashi O. Kaneko 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1981,1(2):159-161
Electron beam experiments in space that have been done and planned in Japan are reviewed. 200eV, 1mA electron beam is emitted from a satellite and several types of wave excitation such as UHF and ωce have been observed. The satellite potential and the energy spectrum of returning electrons are measured by Langmuir probes and electrostatic energy analyser. In rocket experiments of K-10-11, K-10-12, K-9M-57, K-9M-58, K-9M-61 and K-9M-66, several types of electron guns were used whose power ranges from 1mW to 1KW. The rocket potential was measured by Langmuir probes and floating probes and optical line emission measurement and wave measurements were also done. The rocket potential was not so high as expected from the balance with ionospheric plasma but strongly affected by the plasma production by the emitted electron beam and return electrons. 相似文献
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K.I. Gringauz N.M. Shutte A.S. Volokitin E.V. Mishin 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1981,1(2):69-76
The results of measurements made by the retarding potential analyzer of electron fluxes recorded during electron beam injection ~0.5A current pulses and energy 15 or 27 keV during the ARAKS experiment are analyzed. The relatively low rocket potential (~150 V) observed is explained by the formation of a highly conducting region near the rocket. Such a region can be formed via intense plasma waves generated by the beam. This mechanism also explains the heating of the electrons near the rocket. Measurements of electron fluxes with energies of 1 to 3 keV and estimate based on the beam plasma discharge theory agree very well. 相似文献
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为分析碘工质射频离子推力器束流特性,应用粒子云网格算法(PIC),对碘工质射频离子推力器栅极系统进行三维数值仿真。碘工质电离产物中除了大量存在的I+,还包含少量I2+、I2+、I3+几种多价离子。对添加多价离子前后束流特性的仿真结果进行对比,得出该栅极系统离子空间分布、电势分布、离子相空间分布以及束流、束流发散角,并对变密度工况下束流大小进行统计。计算结果表明,程序能较好地模拟离子在栅极系统中的运动情况:添加多价离子后,等离子体悬浮电势有所上升,鞍点电势有所下降,但整体电势分布的变化幅度较小;添加多价离子后束流大小略有增加,束流发散角略有减小,通过理论分析可知仿真所得理论推力及理论比冲均有小幅度增加;放电室等离子体数密度增加到约2.4×1017m-3时,该栅极系统达到了束流引出的极限,后续增大等离子体密度引出束流不增反降。模拟结果可以为碘工质射频离子推力器栅极系统的设计提供参考。 相似文献
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S.A. Elwakil A.M. El-hanbalyA. Elgarayh E.K. El-ShewyA.I. Kassem 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2014
The properties of nonlinear electron-acoustic rogue waves have been investigated in an unmagnetized collisionless four-component plasma system consisting of a cold electron fluid, non-thermal hot electrons obeying a non-thermal distribution, an electron beam and stationary ions. It is found that the basic set of fluid equations is reduced to a nonlinear Schrodinger equation. The dependence of rogue wave profiles on the electron beam and energetic population parameter are discussed. The results of the present investigation may be applicable in auroral zone plasma. 相似文献
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日冕背景下的等离子体尾场效应 总被引:1,自引:0,他引:1
计算了高能脉冲电子束在冷背景和热背景等离子体条件下产生的等离子体尾场(PWF)大小,讨论了高能电子束的速度、密度、长度对等离子体尾场分布的影响。在这基础上,研究了太阳耀斑脉冲相产生的向外逃逸高能脉冲电子束在日冕背景等离子体条件下激发的等离子体尾场分布以及对其捕获电子的加速。 相似文献
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V.S. Dokukin A.K. Markeev E.V. Mishin Ju.Ja. Ruzhin V.V. Fomichev I.A. Zhulin V.N. Ivchenko G.P. Milinevsky R.I. Moisya R.Z. Sagdeev 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1981,1(2):5-15
The rocket experiment ZARNITZA-2 on artificial electron beam injection in the ionosphere was carried out on September 11, 1975. Great attention was paid to the study of phenomena occurring in the near-rocket region. The results of the experiment are discussed in terms of a beam plasma discharge. 相似文献
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T.A. Jacobsen J. Tr∅im B.N. Maehlum M. Friedrich 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1981,1(2):123-127
A “mother-daughter” rocket code-named “Electron 2” was launched from And?ya, Northern Norway in November, 1978. The “daughter”, carrying a 10 keV electron accelerator, was separated from the “mother” payload with a speed of 0.4 m/s. A series of plasma diagnostic instruments were included on the “mother” to study effects produced by the interaction between the electron beam and the ionospheric plasma. Results obtained by two different plasma probes are presented. It was found that pronounced changes in the ambient electron population took place in regions penetrated by the electron beam. Estimates of the dimensions of the disturbed region are presented. 相似文献
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E.V. Mishin Ju.Ja. Ruzhin 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1981,1(2):47-59
The model of beam-plasma discharge near the rocket following electron beam injection into the ionosphere is presented. The dependence of discharge plasma density on neutral atmosphere concentration and beam parameters is found. Radioemission and luminiscence intensities from discharge are estimated. The model is consistent with the data of ARAKS and “Zarnitsa-2” experiments. 相似文献
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V. N. Oraevsky Yu. Ya. Ruzhin V. G. Korobeinikov A. S. Volokitin V. S. Skomarovsky 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1992,12(12):131-134
The paper presents the results and discussion of VLF wave measurements carried out in the course of two rocket experiments on injection of a dense cesium ion beam into the ionosphere at the heights of 165–240 km. The injection was accompanied by enhancement of the broad-band noise by several orders of magnitude. The wave measurements in the frequency range of 1–11 kHz revealed two pronounced frequencies somewhat exceeding that of the lower-hybrid resonance oscillations in the background plasma and the cesium beam. The oscillations were modulated by frequencies close to the ion-cyclotron frequencies of the background plasma. 相似文献
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A C Nelson C A Tobias 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1983,3(8):195-209
Scanning electron micrographs of heavy ion irradiated corneas demonstrate a significant correlation with the heavy ion beam: The average number of plasma membrane lesions per unit area of corneal surface is correlated with the particle fluence of the beam. This observation corroborates what has already been suggested theoretically about heavy ion tracks and what has been shown experimentally through etched plastics, developed emulsions, and bubble chambers. But the new data indicate that particle tracks occur in biological tissues as well, and that a single heavy ion is responsible for each membrane lesion. 相似文献