Effect of inhomogeneous magnetic field on physical processes in a gas-discharge positive column

The transverse distribution of the Charged-particle concentration in the positive column of a gas discharge situated in an inhomogeneous magnetic field is obtained; the dependence of the ionization coefficient on the magnitude of the magnetic field is calculated.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 33–36, June, 1977.     

The universality of phase resonances for disordered systems in a strong magnetic field

The density of states of a three-dimensional disordered system in a strong magnetic field with a periodic back-ground potential is examined. The calculation of the density of states is reduced to the investigation of an effective one-dimensional problem. In the limit of weak disorder the density of states shows anomalies whenever the ratio of the wavelength and the lattice constant is a rational number. These phase resonances are investigated in detail for the band edges and for the middle of the band.     

Possible use of a gas-discharge plasma in an oscillating field to modulate electromagnetic radiation

The conditions for resonance and signal cutoff are determined from the dispersion relation for the complex refractive index for a plane electromagnetic wave propagating in a gas-discharge plasma when a magnetic field H = H₀ + H₁e^jt is imposed on the plasma. The refractive index and absorption are calculated for circularly polarized waves as functions of the alternating magnetic field with _p, _b, andv as parameters. Possible observation of modulation of the transmitted signal is demonstrated.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 94–99, April, 1971.     

Concerning the shift of nonlinear optical resonances in a magnetic field

The shift of components of the magnetic hyperfine structure (MHS) of a vibrational-rotational molecular transition in a weak magnetic field is explored. The numerical data are given for the methane transition at λ=3.39 μm [theF ₂ ⁽²⁾ component of theP(7) line of thev ₃ band]. The shift of the line contour due to the magnetic field is found when the MHS components overlap.     

Electromagnetically induced transparency resonances inverted in magnetic field

The phenomenon of electromagnetically induced transparency (EIT) is investigated in a Λ-system of the ⁸⁷Rb D ₁ line in an external transverse magnetic field. Two spectroscopic cells having strongly different values of the relaxation rates γ_rel are used: an Rb cell with antirelaxation coating (L ~ 1 cm) and an Rb nanometric- thin cell (nanocell) with a thickness of the atomic vapor column L = 795 nm. For the EIT in the nanocell, we have the usual EIT resonances characterized by a reduction in the absorption (dark resonance (DR)), whereas for the EIT in the Rb cell with an antirelaxation coating, the resonances demonstrate an increase in the absorption (bright resonances (BR)). We suppose that such an unusual behavior of the EIT resonances (i.e., the reversal of the sign from DR to BR) is caused by the influence of an alignment process. The influence of alignment strongly depends on the configuration of the coupling and probe frequencies as well as on the configuration of the magnetic field.     

Comment on magnetic e+e- resonances in a central field

Within a simple semiclassical model it is shown that the presence of an external Coulomb field induces only slight changes in the energy of a resonant electron-positron state unless for extremely small distances, while the width increases strongly with the field strength.     

Current effects on high magnetic field resonances in a dot array

In recent studies of disordered quantum dot arrays, it was found that a re-entrant metal–insulator transition occurs in these structures as the gate voltage is varied, even though there is no change in carrier density or disorder. Here, we study resonances that appear with the quantum Hall effect in these dot arrays. Several resonances are observed on the side of the plateaus, which may be due either to charging of isolated islands or to transmission resonances in the quantum point contacts. Heating of the carriers causes these peaks to decrease with an energy relaxation time comparable to that of the dots themselves.     

Ultracold plasma expansion in a magnetic field

We measure the expansion of an ultracold plasma across the field lines of a uniform magnetic field. We image the ion distribution by extracting the ions with a high-voltage pulse onto a position-sensitive detector. Early in the lifetime of the plasma (<20 micros), the size of the image is dominated by the time-of-flight Coulomb explosion of the dense ion cloud. For later times, we measure the 2D Gaussian width of the ion image, obtaining the transverse expansion velocity as a function of the magnetic field (up to 70 G). We observe that the expansion velocity scales as B(-1/2), explained by a nonlinear ambipolar diffusion model with anisotropic diffusion in two different directions.     

The plasma parameter of a positive column in a transverse magnetic field

The effect of a transverse magnetic field on the axial electric field and the electron temperature in a positive column were investigated experimentally. The results are compared with the theory of Beckman.     

Laser-heating of a conoidal plasma in a magnetic field

A self-similar plasma model is used to investigate the heating and the confinement of laser-produced plasmas in a strong magnetic field. Using the Runge-Kutta method, numerical values of plasma temperature, displacement, absorption and velocity as a function of time are obtained for a wide range of experimental conditions using a high power pulsed CO₂ laser incident on a solid target.     

The effect of magnetic field on plasma particles in dusty plasma

In this work, we present the investigation of the formation features and internal structure of dust clouds created in plasma of glow discharge in the external magnetic field corresponding to a range of moderate and strong fields, at which the ion component is magnetized. The analysis of the plasma magnetization in the presence of dust components is carried out. We defined the values of magnetic induction at which the changes in dynamics of plasma particles in magnetic field in light inert gases are expected. The experimental setup was built in two versions. For the purpose of generating of magnetic field, the first setup was equipped with ordinary magnetic coils, and the second one included a superconducting solenoid. The discharge tubes, the main chambers where plasma was ignited and maintained in a glow discharge in lowered pressure, also have certain peculiarities, which we describe below. While using helium as a bulk gas, our study focused only on the dust trap in the region of narrowing discharge current. For neon, we used two traps: the striation trap and one just mentioned above placed in the narrowing of the discharge tube. As a result, the steady dust structures in a glow discharge under the magnetization of ions and electrons were obtained for the first time. Dust structures were rotated and tended to form a dust cluster and shell structure. A number of parameters of magnetization achieved in experiments were calculated.     

Cold neutral plasma in a quantizing magnetic field

The chemical potential of a relativistic and an ultrarelativistic electron gas and the energy of an ultrarelativistic electron gas at T = 0 are expressed analytically as functions of the magnetic field. The possible application of these expressions to the investigation of super-compressed matter in the presence of superstrong magnetic fields is discussed.