The effect of plasma drift on the electromagnetic cyclotron instability

It is shown that the drift of plasma across a homogeneous magnetic field causes the generation of a wave electric field which, for waves propagating along the magnetic field in the whistler mode, is in the direction of the magnetic field. This leads to Landau damping of the wave field by the background electron distribution, simultaneously with amplification via the electromagnetic cyclotron instability. The drift velocity of the plasma for zero net growth of a whistler mode signal is calculated. It is suggested that such a process occurs in the equatorial region of the magnetosphere during a geomagnetic storm and accounts for the missing band of emissions at half the equatorial gyrofrequency.     

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讨论了静态非均匀磁场中的磁场旋度对带电粒子引导中心漂移的影响。运用三维矢量分析的方法,将带电粒子垂直于磁场运动所引起的磁场漂移分为两项,分别由磁场的曲率和磁场的旋度决定。给出了螺旋状环形磁场中由磁场旋度引起的磁场漂移的近似表达式,讨论了该漂移成分对于该磁场中通行粒子轨道和捕获粒子轨道的可能影响。结果表明,带电粒子垂直于磁场运动所引起的磁场漂移主要由磁场的曲率决定,而磁场旋度对该漂移的影响比较微弱。     

磁场旋度对磁场漂移的影响

讨论了静态非均匀磁场中的磁场旋度对带电粒子引导中心漂移的影响。运用三维矢量分析的方法,将带电粒子垂直于磁场运动所引起的磁场漂移分为两项,分别由磁场的曲率和磁场的旋度决定。给出了螺旋状环形磁场中由磁场旋度引起的磁场漂移的近似表达式,讨论了该漂移成分对于该磁场中通行粒子轨道和捕获粒子轨道的可能影响。结果表明,带电粒子垂直于磁场运动所引起的磁场漂移主要由磁场的曲率决定,而磁场旋度对该漂移的影响比较微弱。     

Light-induced drift of ions in a magnetic field

The effect of a magnetic field on the ion drift in a weakly ionized gas under the combined action of the light-induced drift and light pressure is studied theoretically. It is shown that, under the action of light, a component of ion drift velocity transverse to the direction of propagation of radiation may appear in a weakly ionized gas upon the application of an external magnetic field. It is shown that the Lorentz force acting on ions in the magnetic field radically changes the dependence of the ion drift velocity on the radiation frequency detuning. It is predicted that the ion drift velocity component along the direction of radiation must reverse its sign upon an increase in the magnetic field and an anomalous light-induced drift may be observed.     

Mechanism of drift of stripe magnetic domains in ferrite-garnet single crystals

The drift of stripe magnetic domains in (111) single-crystal ferrite-garnet plates in an alternating magnetic field (25–1000 Hz) has been investigated. The dependences of the drift velocity of stripe domains on the field frequency and amplitude have been obtained for magnetic fields of different orientations. A dislocation drift mechanism is proposed. Enhanced motion of magnetic dislocations in a system of stripe domains is established.     

Influence of a magnetic field on the light-induced ion drift

It is shown that the velocity component transverse to the radiation propagation direction can arise in the light-induced ion drift (LIID) after applying an external magnetic field to a weakly ionized gas. It is predicted that the projection of the ion drift velocity onto the radiation direction changes its sign with an increase in the magnetic field, resulting in the anomalous LIID.     

Theorie der Bewegung geladener Teilchen in richtungskonstanten zeitabhängigen Magnetfeldern und elektrischen Zusatzfeldern

The motion of a charged particle in spatially homogeneous electric and magnetic fields is calculated for the case of the magnetic field to have a constant direction and its intensity to vary with an arbitrary power of time. The special case of a linearly increasing magnetic field is treated in detail taking into account a friction force proportional to the particle velocity. Generally, the equations of motion are reduced to a single differential equation of second order which is integrated exactly. The higher transcendental functions appearing in the solution are then approximated by elementary functions. Thus asymptotic approximative equations of a very simple form are obtained for position, velocity, kinetic energy and magnetic moment of the particle. The dependence of the particle orbit on the initial values of position and velocity and on the properties of the magnetic field is studied, and it is shown, how the particle motion is a helical motion superposed by a drift. The influence of the electric field induced by the time dependent magnetic field on the particle motion is considered in detail. For an additional electric field being present a drift formula is derived which is a generalization of the well-known ?? × ?? 93 drift for constant fields.     

On the influence of a weak magnetic field on the drift motion of charged particles

The results obtained in [1] are generalized to the case when an arbitrarily oriented magnetic field is present by allowance for the influence of a magnetic field with cyclotron frequency less than the collision frequency on the dependence of the drift velocity on the velocity of random motion (Langevin equation). A study is made of the influence of a magnetic field on the equation of drift motion derived in [1] and this field is allowed for in the previously obtained results of the solution of that equation.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 69–72, May, 1972.     

Effect of E × B electron drift and plasma discharge in dc magnetron sputtering plasma

Study of electron drift velocity caused by Etimes B motion is done with the help of a Mach probe in a dc cylindrical magnetron sputtering system at different plasma discharge parameters like discharge voltage, gas pressure and applied magnetic field strength. The interplay of the electron drift with the different discharge parameters has been investigated. Strong radial variation of the electron drift velocity is observed and is found to be maximum near the cathode and it decreases slowly with the increase of radial distance from the cathode. The sheath electric field, E measured experimentally from potential profile curve using an emissive probe is contributed to the observed radial variation of the electron drift velocity. The measured values of the drift velocities are also compared with the values from the conventional theory using the experimental values of electric and magnetic fields. This study of the drift velocity variation is helpful in providing a useful insight for determining the discharge conditions and parameters for sputter deposition of thin film.     

Hot-Electron Magneto-Transport in InSb

The balance equations are used to investigate the hot electron magneto-transport in narrowgap semiconductor InSb at 77 K in crossed weak magnetic field and electric field. In the case of vanishing transverse velocity, the drift mobility and the Hall mobility are calculated and it is shown that the Hall factor in InSb at 77K is less than 1 and decreases with electric field. In the case of vanishing transverse electric field, the longitudinal velocity and the transverse velocity are calculated as a function of the magnetic field and the electric field. The effect of the magnetic field on the longitudinal velocity is different from that on the transverse velocity.     

11-year and 22-year variations in the anisotropy of galactic cosmic rays

An 11-year modulation of the electric drift anisotropy directed across the force lines of the interplanetary magnetic field and a 22-year modulation of the magnetic drift anisotropy along the interplanetary magnetic field have been found on the basis of the data of the Yakutsk underground complex of muon telescopes. Some specific features of the anisotropy during the pole reversal of the total solar magnetic field are discussed.     

Double layers in a field-aligned current driven plasma

The solutions of small amplitude ion acoustic double layers in current-carrying plasma in the presence of the magnetic field have been presented. The electron beam along the magnetic field has only been considered and the drift velocity assumed to be less than the electron thermal velocity. The velocity, the width and the potential of such DLs are calculated.     

Dynamic drift of the magnetic domains in ferrite-garnet crystals

The drift of stripe-domain walls in a (111) ferrite-garnet plate with orthorhombic anisotropy and quality factor Q < 1 in an alternating magnetic field of 30–1000 Hz was investigated. The obtained experimental dependences of the domain wall drift velocity on the magnetic field frequency and amplitude are compared to the corresponding theoretical dependences.     

托卡马克电场电子注入的漂移电子束研究

 研究了漂移电子束中电子的运动规律, 得到了电子在外加电场、纵磁场和电子束自场中的运动轨迹和漂移速度表达式, 并就它们的成束条件、成束形状和电压要求以及束的稳定性条件进行了比较和讨论, 认为阴极垂直于纵磁场放置更好一些。     

Conditions for the existence of a positively charged structure in a Penning discharge

An analytical model is developed for the high-current form of a low-pressure glow discharge in a magnetic field. Expressions are derived for the critical magnetic induction and critical pressure, below which it becomes impossible for this form of discharge to exist. It is shown that the transition from the high-voltage form to the high-current form of discharge with increasing pressure is not attributable to an increase in the ionization rate, but to an increase in the drift velocity of plasma electrons across the magnetic field. Estimates based on the expressions derived in the article agree in order of magnitude with the experimental data. It is shown that the region in which discharge exists can change considerably in the presence of electron emission. Zh. Tekh. Fiz. 68, 56–63 (July 1998)     

Theory and simulation of an 85 GHz quasioptical gyroklystron experiment

The linear theory used to design a two-resonator 85 GHz quasioptical gyroklystron with a nonuniform magnetic field is presented. It is shown that a tapered magnetic field in the prebunching resonator has a relatively small effect on the electron bunching parameter. The effect of velocity spread of the electron beam can be minimized by adjusting the magnetic field strength in the two resonators. Measured amplifier performance is in good agreement with calculations from the nonlinear multimode simulation code. Gyrophase bunching of the electrons is preserved over the long drift region (30 radiation wavelengths) even though no attempt has been made to minimize the velocity spread of the beam.     

Dynamics of <Emphasis Type="Italic">ab</Emphasis>-type domain walls in magnets with quadratic magnetoelectric interaction

The dynamics of the ab-type 180-degree domain walls was studied in weak ferromagnets with quadratic magnetoelectric interaction in alternating magnetic and electric fields. The features of the oscillatory and drift motion of the domain walls are discussed. The drift velocity of the ab-type domain walls as a function of the frequency and phase shift of the external fields is obtained. The possibility of the drift of the domain walls in a purely electric field is established.     

Precession of an electron-magnetohydrodynamic field-reversed configuration

A field-reversed configuration is generated in a large laboratory plasma in the parameter regime of electron magnetohydrodynamics. During its free relaxation, the magnetic moment is observed to precess when tilted from its original axis. The precession velocity is the electron drift velocity in the toroidal current layer. The precession is a manifestation of frozen-in field lines in a moving electron fluid.     

负径向电场对荷电粒子运动的影响及其数值模拟

从负径向电场产生的电漂移改变荷电粒子运动的极向运动速度着手,推导出在负径向电场存在时安全因子的表达式,分析了安全因子对荷电粒子漂移位移和运动轨迹的影响。建立了在负径向电场条件下,荷电粒子在梯度磁场和曲率磁场中运动数学模型。通过数值模拟,获得了通行粒子、香蕉粒子的漂移位移和运动轨迹所呈现出的新特点和规律:负径向电场改变了荷电粒子的最大漂移位移。当荷电粒子的极向运动速度增加时,最大漂移位移减小,反之增大;改变了荷电粒子的运动轨迹,通行粒子的轨亦可能变为香蕉粒子的轨迹,香蕉粒子的轨迹可能变为通行粒子的轨迹,当电场达到足够的强度时,均成为在极向上顺时针运动的通行粒子轨迹。     

ELECTRON DIFFUSION IN A NON-UNIFORM ELECTRIC FIELD AND A UNIFORM MAGNETIC FIELD

A Monte Carlo simulation technique has been used to model the electron transport beharlot, especially the electron diffusion motion, in the cathode fall region of a glow discharge under the influence of a non-uniform electric field and a transverse magnetic field perpen-dicular to the cathode sheath electric field. Three types of collisions (elastic, excitation and ionization) are taken into account in our model. The electron free flying time is determined by the electron-neutral atom collision frequency. We focus attention on the electron diffusion distance and velocity. The electron-neutral atom collision processes and the electron drift velocity are also studied. The results indicate that with the increase of the magnetic field the electron diffusion distance increases and the electron diffusion velocity decreases. The results Mso show that the collision processes are enhanced by the magnetic field, this is in agreement with the experimental result. However, the axial magnetic field does not affect the electron transport behavior.