Meteor trail drift research based on baseline observations

We analyze the results of a rare long-lived quasisymmetric ellipsoidal-annular meteor trail recorded on November 18, 2017 by two optical all-sky cameras, spaced at a distance of 150 km. The analysis is based on astrometric processing results with the use of baseline measurement methods. We determine spatial-kinematic characteristics of the meteor trail, and find features of its evolution. The ignition and extinction heights of the meteor were in the range 75–120 km. The estimate of the meteor brightness gives the absolute magnitude value of about –7.3m. It is shown that the distribution of all parts of the long-lived meteor trail occurs in the same plane at a height of ~90 km at a speed of ~320 m/s and, apparently, cannot be a consequence of an air mass movement. The total time of the meteor trail observation was more than 30 min. We offer possible explanations for the results obtained in the context of upper atmosphere processes

New experimental data for the decays ϕ→μ+μ−\phi\to\mu^+\mu^- and ϕ→π+π−\phi\to\pi^+\pi^- from SND detector

The processes $e^+e^-\to\mu^+\mu^-$ and $e^+e^-\to\pi^+\pi^-$ have been studied with SND detector at VEPP-2M $e^+e^-$ collider in the vicinity of $\phi(1020)$ resonance. The branching ratios $B(\phi\to\mu^+\mu^-)=(3.30\pm 0.45\pm 0.32)\times 10^{-4}$ and $B(\phi\to\pi^+\pi^-)=(0.71\pm 0.11\pm 0.09)\times 10^{-4}$ were obtained.Comment: 5 pages, 4 figures, talk given at 8th International Conference on Hadron Spectroscopy (HADRON 99), Beijing, China, 24-28 Aug 199

The process e+e−→π+π−π0e^+e^-\to\pi^+\pi^-\pi^0 in the energy range 2E_0=1.04 - 1.38 GeV

In the experiment with the SND detector at VEPP-2M e^+e^- collider the process $e^+e^-\to\pi^+\pi^-\pi^0$ was studied in the energy range 2E_0 from 1.04 to 1.38 GeV. A broad peak was observed with the visible mass $M_{vis}=1220\pm 20$ MeV and cross section in the maximum $\sigma_0\simeq 4$ nb. The peak can be interpreted as a $\omega$-like resonance $\omega (1200)$.Comment: 10 pages LATEX and 5 figure

A molecular dynamics study on the equilibrium magnetization properties and structure of ferrofluids

We investigate in detail the initial susceptibility, magnetization curves, and microstructure of ferrofluids in various concentration and particle dipole moment ranges by means of molecular dynamics simulations. We use the Ewald summation for the long-range dipolar interactions, take explicitly into account the translational and rotational degrees of freedom, coupled to a Langevin thermostat. When the dipolar interaction energy is comparable with the thermal energy, the simulation results on the magnetization properties agree with the theoretical predictions very well. For stronger dipolar couplings, however, we find systematic deviations from the theoretical curves. We analyze in detail the observed microstructure of the fluids under different conditions. The formation of clusters is found to enhance the magnetization at weak fields and thus leads to a larger initial susceptibility. The influence of the particle aggregation is isolated by studying ferro-solids, which consist of magnetic dipoles frozen in at random locations but which are free to rotate. Due to the artificial suppression of clusters in ferro-solids the observed susceptibility is considerably lowered when compared to ferrofluids.Comment: 33 pages including 12 figures, requires RevTex

Plasma heating and confinement in the GOL-3 multiple mirror trap

Experiments on plasma confinement in a multiple mirror configuration are carried out at GOL-3 facility in Novosibirsk. Feature of experiments at this facility is high plasma density (up to 5⋅10²¹ m⁻³ ). High ion temperature (up to 2 keV) essentially differs the regime with multimirror configuration from previously studied plasma heating by the Ebeam in a uniform magnetic field. Physical mechanism of effective heating of plasma ions, substantially dependent on corrugation of the magnetic field is discussed. In this paper the new experimental data from the GOL-3 facility are presented and the main attention to a stage of ion heating is addressed.Експерименти по нагріванню й утриманню плазми в багатопробковій пастці проводяться на установці ГОЛ- 3 у Новосибірську. Особливістю плазми в цій пастці є її відносно висока (до 5⋅10²¹ м⁻³ ) густина. Нагрівання плазми релятивістським електронним пучком у багатопробковій пастці істотно відрізняється від нагрівання в простому соленоїді тим, що спостерігається збільшення іонної температури аж до 2 кэВ. У роботі обговорюється механізм швидкого нагрівання іонів і представляються нові експериментальні результати, отримані на установці ГОЛ-3.Эксперименты по нагреву и удержанию плазмы в многопробочной ловушке проводятся на установке ГОЛ-3 в Новосибирске. Особенностью плазмы в этой ловушке является ее относительно высокая (до 5⋅10²¹ м⁻³ ) плотность. Нагрев плазмы релятивистским электронным пучком в многопробочной ловушке существенно отличается от нагрева в простом соленоиде тем, что наблюдается увеличение ионной температуры вплоть до 2 кэВ. В работе обсуждается механизм быстрого нагрева ионов и представляются новые экспериментальные результаты, полученные на установке ГОЛ-3

Plasma heating and confinementat the GOL-3-II facility

Results of experiments on plasma heating and confinement in multimirror open trap GOL-3-II are presented. This facility is intended for heating and confinement of a relatively dense (10¹⁵-10¹⁷ cm⁻³) plasma in axially-symmetrical magnetic system. The plasma heating is provided by a high-power electron beam (1 MeV, 30 kA, 8 µs, 200 kJ). Results of the experiments with multimirror configuration of the device indicate that the confinement time of the plasma with ne ~ (0,5÷5).10¹⁵ cm⁻³ and Te ~1 keV increases more than order of magnitude in comparison with single mirror device

Search for the radiative decay η→π0γγ\eta \to \pi^0 \gamma \gamma in the SND experiment at VEPP-2M

The $\eta \to \pi^0 \gamma \gamma$ decay was investigated by the SND detector at VEPP-2M $e^+e^-$ collider in the reaction $e^+e^-\to\phi\to \eta\gamma$. Here we present the results and some details of this study. We report an upper limit (90% c.l.) $Br(\eta \to \pi^0 \gamma \gamma)<8.4\times 10^{-4}$ as our final result. Our upper limit does not contradict the earlier measurement by GAMS spectrometer. To facilitate future studies a rather detailed review of the problem is also given.Comment: 24 pages, 6 figures, LaTex. To be published in Nucl. Phys.

Active Galactic Nuclei at the Crossroads of Astrophysics

Over the last five decades, AGN studies have produced a number of spectacular examples of synergies and multifaceted approaches in astrophysics. The field of AGN research now spans the entire spectral range and covers more than twelve orders of magnitude in the spatial and temporal domains. The next generation of astrophysical facilities will open up new possibilities for AGN studies, especially in the areas of high-resolution and high-fidelity imaging and spectroscopy of nuclear regions in the X-ray, optical, and radio bands. These studies will address in detail a number of critical issues in AGN research such as processes in the immediate vicinity of supermassive black holes, physical conditions of broad-line and narrow-line regions, formation and evolution of accretion disks and relativistic outflows, and the connection between nuclear activity and galaxy evolution.Comment: 16 pages, 5 figures; review contribution; "Exploring the Cosmic Frontier: Astrophysical Instruments for the 21st Century", ESO Astrophysical Symposia Serie

Giant Planet Formation and Migration

© 2018, The Author(s). Planets form in circumstellar discs around young stars. Starting with sub-micron sized dust particles, giant planet formation is all about growing 14 orders of magnitude in size. It has become increasingly clear over the past decades that during all stages of giant planet formation, the building blocks are extremely mobile and can change their semimajor axis by substantial amounts. In this chapter, we aim to give a basic overview of the physical processes thought to govern giant planet formation and migration, and to highlight possible links to water delivery.S.-J. Paardekooper is supported by a Royal Society University Research Fellowship. A. Johansen is supported by the Knut and Alice Wallenberg Foundation, the Swedish Research Council (grant 2014-5775) and the European Research Council (ERC Starting Grant 278675-PEBBLE2PLANET)