摘要:

The current density of a low‐density collisionless plasma, confined in static equilibrium by a strong externally applied static magnetic field, is obtained in the limit of adiabatic motion for the charged particles. When there is no net streaming, to zero order in &egr;: the mass‐to‐charge ratio, along the field lines of the magnetic field, then the current density is of first order in &egr;, and its component along the field line is produced by three contributions. The first is due to the shear drift of the guiding centers along the field line. The second is due to the zero‐order drift of the guiding centers along the field line, and the velocity space asymmetry in the first‐order correction to the lowest‐order distribution function. This asymmetry is due to the shear in the field lines. The third contribution is due to the component of the curl of the magnetization along the field line and is also related to the shear. A local macroscopic equilibrium relation for the gradient of the pressure is obtained from the divergence of the current density.

ISSN:0031-9171    

DOI:10.1063/1.1692197

出版商:AIP    

年代:1968

数据来源: AIP

摘要:

An anisotropic plasma exhibits a transverse instability due to the mutual attraction of the microscopic current elements. A detailed study is made of this instability in an electron‐ion plasma without any external magnetic field. The system is characterized by a temperature tensor and described by a quasi‐Maxwellian distribution function. The dielectric tensor for such a system is calculated and then the dispersion relation is considered. It is found that there are two unstable modes: (i) a purely transverse mode and (ii) a coupled or transverse‐longitudinal mode. The latter separates into two branches: (a) the first is an essentially unstable quasitransverse mode, (b) the second is the quasi‐longitudinal ion acoustic mode driven into instability through its interaction with the quasitransverse mode. Growth rate,kand angular dependence, domain of instability, and polarization are analyzed in detail.

ISSN:0031-9171    

DOI:10.1063/1.1692198

出版商:AIP    

年代:1968

数据来源: AIP

摘要:

By the discharge of condensers, a current is driven axially through a plasma column located in a mirror field. The maximum value of the current is typically 5000 A and the frequency typically1Mc/sec. It is found that under a variety of circumstances, 3‐4% of the energy initially stored in condensers is transferred to perpendicular energy of the plasma. A substantial part of the energy is transferred to ions. The ion energy spectrum has been measured in one case and within experimental error found Maxwellian with a temperature close to 500 eV. Measurements of x rays emitted when a tantalum target is placed in the plasma show that very few high‐energy electrons (> 5keV) are present except while the axial current flows. It is found that the energy transferred to the plasma is proportional to the square of the maximum current; this suggests that efficiencies higher than 4% may be obtained.

ISSN:0031-9171    

DOI:10.1063/1.1692199

出版商:AIP    

年代:1968

数据来源: AIP

摘要:

In a linear quadrupole plasma containment device, lacking internal supports for the current conductors, the flux of charged particles from the main plasma volume is measured directly. With rf‐produced plasmas(nebetween 1010− 1012cm−3, Te˜ 10 eV, Ti< 1 eV), the end losses are only a small fraction of the total losses. Most of the plasma is lost outwards in a direction perpendicular to the current conductors (radial loss). With gun‐injected plasmas, the radial loss is usually smaller than the end loss but is still nonclassical.

ISSN:0031-9171    

DOI:10.1063/1.1692200

出版商:AIP    

年代:1968

数据来源: AIP

摘要:

An experimental study has been carried out on coherent forward scattering of microwaves from ion acoustic waves in alkali plasmas in a nonlinear regime. The experimental apparatus allowed quantitative measurements to be made with good accuracy. Geometrical and diffraction effects have been avoided by using a plasma filled waveguide. The dependence of scattering cross section on the amplitude of ion acoustic waves and on the frequency of the incident radiation has been studied in detail. The experimental results are in good agreement with the theoretical results.

ISSN:0031-9171    

DOI:10.1063/1.1692201

出版商:AIP    

年代:1968

数据来源: AIP

摘要:

A method is described of extending theories of heat transfer and shear between coaxial cylinders and concentric spheres to the case of arbitrary accommodation coefficients at both inner and other surfaces. Correction formulas for these problems are derived.

ISSN:0031-9171    

DOI:10.1063/1.1692203

出版商:AIP    

年代:1968

数据来源: AIP

摘要:

Similar solutions are obtained for the unsteady magnetohydrodynamic Couette flow with suction. Both uniform and time‐dependent magnetic fields are considered. It is shown that the magnetohydrodynamic flows can be obtained through the analysis of viscous flow.

ISSN:0031-9171    

DOI:10.1063/1.1692204

出版商:AIP    

年代:1968

数据来源: AIP

摘要:

The predictions of velocity profiles in hydromagnetic channel flows derived during an earlier study compare satisfactorily with recent experimental measurements of Brouillette and Lykoudis.

ISSN:0031-9171    

DOI:10.1063/1.1692205

出版商:AIP    

年代:1968

数据来源: AIP

摘要:

Essential features of general two‐dimensional steady magneto‐gasdynamic flows are shown. For the special class of zero transverse electric field flow, new invariants along streamlines and their intrinsic properties are given.

ISSN:0031-9171    

DOI:10.1063/1.1692206

出版商:AIP    

年代:1968

数据来源: AIP

摘要:

The experimental observation of the reflection of ion acoustic waves from a negatively biased grid immersed in a plasma is reported. Reflection is detected only in the region where the plasma is “perturbed.”

ISSN:0031-9171    

DOI:10.1063/1.1692207

出版商:AIP    

年代:1968

数据来源: AIP