Mirror instability in a plasma with cold gyrating dust particles

In this work linear stability analysis of a magnetized dusty plasma with an anisotropic dust component having transversal motions much stronger than motions parallel to the external magnetic field, and isotropic light plasma components is described. Such a situation presumably establishes in a shock compressed space dusty plasma downstream the shock front. Oblique low-frequency magneto-hydrodynamic waves ($\omega\ll \omega_{cd}$, $\omega_{cd}$ being the dust cyclotron frequency) are shown to be undergone to the mirror instability. Consequences for nonthermal dust destruction behind shock fronts in the interstellar medium are discussed.Comment: 13 pages, 5 figs, accepted to Phys. Pasma

Once More About the Possibility of Determining the Local Electron Concentration by the Dispersion Method with the Help of AES and on New Ionization Maxima in the Ionosphere

Reliability of ionospheric density measurements by satellites using dispersion metho

Irreducible modules over finite simple Lie conformal superalgebras of type K

We construct all finite irreducible modules over Lie conformal superalgebras of type KComment: Accepted for publication in J. Math. Phys

An Antenna with a Feeder for a Superconducting Terahertz Josephson Oscillator with Phase Locking

A principal layout of a Josephson terahertz radiation oscillator integrated with a transmitting antenna-lens system and a harmonic mixer (HM) for phase locking of radiation has been proposed and was successfully implemented. Two antenna-feeder systems designed for the central frequencies of 0.3 and 0.6 THz and located on the same chip with the oscillator are numerically simulated and fabricated. A microstrip transmission line between the oscillator and the antenna is used as the feeder. A study was carried out on matching the oscillator power and HM for two designs; the frequency range of pumping HM was 0.25-0.45 and 0.5-0.68 THz for the designs at 0.3 and 0.6 THz, respectively. Good agreement was obtained between experimental results and numerical simulations. A study of the spectral characteristics of the radiation of the oscillator into the external space for the 0.6 THz design using a superconducting integrated spectrometer was carried out. The linewidth of an emission line in free-running regime was of the order of several megahertz; in the phase locking regime down to tens of kilohertz with a signal-to-noise ratio of more than 20 dB was obtained

PERIODIC SOLUTIONS OF A NON-SMALL AMPLITUDE OF THE QUASILINEAR EQUATION FOR OSCILLATIONS OF AN I-BEAM

The problem of time-periodic solutions of the quasilinear equation of forced oscillations of an I-beam with hinged ends is investigated. The nonlinear summand and the right side of the equation are time periodic functions. The paper studies the case when the time period is commensurate with the length of the beam. The solution is sought in the form of a Fourier series. To prove the convergence of the Fourier series and their derivatives, we study the eigenvalues of the differential operator corresponding to the linear part of the equation. Conditions are obtained under which the kernel of a differential operator is finite-dimensional and the inverse operator is completely continuous on the complement of the kernel. A lemma on the existence and regularity of solutions of the corresponding linear problem is proved. The proof is based on the properties of the sums of the Fourier series. A theorem on the existence and regularity of a periodic solution is proved if the nonlinear term satisfies the non-resonance condition at infinity. The non-resonance condition implies the fact that, for large values of the argument, the graph of the non-linear term does not intersect the straight lines whose slope is an eigenvalue of the linear part of the equation. In the proof of the theorem, an a priori estimate is made of the solutions of the corresponding operator equation and the Leray-Schauder principle of a fixed point is applied. Additional conditions are obtained under which the periodic solution found in the main theorem is unique

Restricted infinitesimal deformations of restricted simple Lie algebras

We compute the restricted infinitesimal deformations of the restricted simple Lie algebras over an algebraically closed field of characteristic different from 2 and 3.Comment: 15 pages; final version, to appear in Journal of Algebra and Its Application

Low-Noise Sis Receivers for New Radio-Astronomy Projects

We have developed, manufactured, and tested a waveguide mixer in the range 211-275 GHz on the basis of the superconductor-insulator-superconductor (SIS) tunnel structures. The methods of manufacturing high-quality tunnel structures on quartz substrates have been worked out. To extend the receiver band, the Nb/AlOx/Nb and Nb/AlN/NbN tunnel junctions with a high current density of up to 20 kA/cm2 are employed. The dependence of the characteristics of the receiving elements on the signal frequency is simulated for the intermediate-frequency band 4-12 GHz. The measurements demonstrate a good agreement of the input band of the receiving structures with the calculated results. The uncorrected noise temperature of the receiver amounts to 24 K at a frequency of 265 GHz, which is only two times higher than the quantum limit. The receivers under development are intended for a number of newly-built ground-based radio telescopes ("Suffa" and LLAMA), as well as for the "Millimetron" space program

Morphology of the tropopause layer and lower stratosphere above a tropical cyclone : a case study on cyclone Davina (1999)

During the APE-THESEO mission in the Indian Ocean the Myasishchev Design Bureau stratospheric research aircraft M55 Geophysica performed a flight over and within the inner core region of tropical cyclone Davina. Measurements of total water, water vapour, temperature, aerosol backscattering, ozone and tracers were made and are discussed here in comparison with the averages of those quantities acquired during the campaign time frame. Temperature anomalies in the tropical tropopause layer (TTL), warmer than average in the lower part and colder than average in the upper TTL were observed. Ozone was strongly reduced compared to its average value, and thick cirrus decks were present up to the cold point, sometimes topped by a layer of very dry air. Evidence for meridional transport of trace gases in the stratosphere above the cyclone was observed and perturbed water distribution in the TTL was documented. The paper discuss possible processes of dehydration induced by the cirrus forming above the cyclone, and change in the chemical tracer and water distribution in the lower stratosphere 400–430 K due to meridional transport from the mid-latitudes and link with Davina. Moreover it compares the data prior and after the cyclone passage to discuss its actual impact on the atmospheric chemistry and thermodynamics