A5087089858- Solar and Space Plasma Dynamics
- Ionosphere and magnetosphere dynamics
- Astro and Planetary Science
- Geomagnetism and Paleomagnetism Studies
- Earthquake Detection and Analysis
- Geophysics and Gravity Measurements
- Magnetic confinement fusion research
- Particle accelerators and beam dynamics
- Stellar, planetary, and galactic studies
- Gamma-ray bursts and supernovae
- Particle Accelerators and Free-Electron Lasers
- Solar Radiation and Photovoltaics
- Oil, Gas, and Environmental Issues
- Gyrotron and Vacuum Electronics Research
- Astrophysics and Cosmic Phenomena
- Atmospheric Ozone and Climate
- Astronomical Observations and Instrumentation
- Statistical and numerical algorithms
- Radio Wave Propagation Studies
- Laser-induced spectroscopy and plasma
- Advanced Thermoelectric Materials and Devices
- Guidance and Control Systems
- solar cell performance optimization
- Advanced Optical Sensing Technologies
- Field-Flow Fractionation Techniques
Pulkovo Observatory
2015-2024
Nizhny Novgorod State University of Architecture and Civil Engineering
2019-2021
Chinese Academy of Sciences
2013-2019
National Astronomical Observatories
2019
National Research University Higher School of Economics
2018
N. I. Lobachevsky State University of Nizhny Novgorod
2018
Radiophysical Research Institute
2003-2014
Russian Academy of Sciences
1998-2014
Purple Mountain Observatory
2012-2013
Misato Observatory
2010
The Heidelberg-Moscow experiment gives the most stringent limit on Majorana neutrino mass. After 24 kg yr of data with pulse shape measurements, we set a lower half-life $0\ensuremath{\nu}\ensuremath{\beta}\ensuremath{\beta}$ decay in ${}^{76}\mathrm{Ge}$ ${T}_{1/2}^{0\ensuremath{\nu}}\ensuremath{\ge}5.7\ifmmode\times\else\texttimes\fi{}{10}^{25}\mathrm{yr}$ at $90%$ C.L. (after PDG98 [C. Caso et al., Eur. Phys. J. C3, 1 (1998]), sensitivity being...
Sufficiently thick and dense coronal loops can support global sausage magnetoacoustic modes. We demonstrate that the oscillation period of this mode, calculated in straight cylinder approximation, is determined by length loop, not its diameter, as it was previously assumed. The existence condition for mode ratio loop to diameter be less than about a half square root density contrast ratio. This has maximum magnetic field perturbation at apex nodes footpoints. 14-17 s quasi-periodic...
A microwave burst with quasi-periodic pulsations was studied high spatial resolution using observations the Nobeyama Radioheliograph (NoRH). We found that time profiles of emission at 17 and 34 GHz exhibit (with two well defined periods 14–17 s 8–11 s) variations intensity different parts an observed flaring loop. Detailed Fourier analysis shows P1 spectral component to be dominant top, while P2 one near feet The are synchronous top in both legs correlated each other but correlation is not...
The dependence of the period sausage oscillations coronal loops on length together with depth and steepness radial profile are determined. We performed a parametric study linear axisymmetric fast magnetoacoustic (sausage) modeled as field-aligned low-β plasma cylinder smooth inhomogeneity density in direction. decreases smoothly Sausage impulsively excited by perturbation velocity, localized at axis harmonic longitudinal coordinate. initial results either leaky or trapped oscillation,...
We present numerical calculations of the intensity, degree polarization, and spectral index gyrosynchrotron emission produced by fast electrons with anisotropic pitch-angle distributions. The anisotropy is found to affect substantially. intensity can change up a few orders magnitude at optically thin region compared isotropic case. local value changes considerably anisotropy. X-mode polarization increases for loss cone distributions decreases beamlike Moreover, sense correspond ordinary wave...
A recent study by Nakariakov and coworkers pointed out that the dispersion relation of MHD sausage-mode oscillations has been incorrectly applied to coronal loops, neglecting highly dispersive nature phase speed long-wavelength cutoff wavenumber. In light these new insights, we revisit previous observations have interpreted in terms loops come following conclusions: (1) fast sausage MHD-mode require such a high electron density imposed wavenumber they can only occur flare (2) previously...
Nobeyama Radioheliograph (NoRH) microwave data provide us with unique information about the radio brightness distribution along flaring loops. In particular, it has been found that for several events extended looplike sources well resolved NoRH, maximum at 17 and 34 GHz is located top of corresponding The detailed analysis these strongly suggests mildly relativistic electrons an loop must be highly inhomogeneous: accelerated are concentrated in upper part loop. This finding imposes important...
Currently available models of one the most intriguing types unsteady rf solar emission, millisecond radio spikes, are discussed. A comparative analysis models' implications and body existing data yields an outline realistic spike model possible. The spikes produced by cyclotron maser mechanism. cone instability is caused fast electrons distributed over energies according to a (piecewise) power law. angular part distribution function (whose exact form is, as yet, undetermined) suffers...
Aims. We aim to perform a spatially resolved analysis of quasi-periodic pulsation event from 8th May 1998 using microwave data the Nobeyama Radioheliograph and Radiopolarimeter, X-ray Yohkoh satellite.
High-resolution radio observation of Nobeyama Radioheliograph at 17 and 34 GHz allowed studying the dynamics microwave brightness distribution along giant limb flaring loop in event 2002 August 24. It is found that on rising phase burst was highly asymmetric, with a strong maximum near southern footpoint (SFP) much weaker enhancements top (LT) northern footpoint. On decay phase, LT gradually became most bright. The similar are shown to happen for all major temporal subpeaks burst. Results...
Theoretical and experimental study of fast electron beams attracts a lot attention in the astrophysics laboratory.In case solar flares problem reliable beam detection diagnostics is exceptional importance.This paper explores fact that moving oblique to magnetic field or along with some angular scatter around propagation direction can generate microwave continuum bursts via gyrosynchrotron mechanism.The characteristics produced by differ from those isotropic loss-cone distributions, which...
Mixed-layer compounds from the tetradymite group, in range Bi2Te3-Bi8Te3, were studied by HRTEM. The formula S′(Bi2kX3)·L′[Bi2(k+1)X3] (X = chalcogen; S′, L′ number of short and long modules, respectively) was introduced as a working model. Diffraction patterns show that all phases are N-fold (N layers stacking sequence) superstructures rhombohedral subcell with c/3 d1 ~ 0.2 nm. patterns, two brightest reflections about middle d1*, described monotonic decrease modulations increase Bi: (1) q...
Corona structures and processes during the pre-impulsive stage of solar eruption are crucial to understanding physics leading subsequent explosive energy release. Here we present first microwave imaging study a hot flux rope structure an eruptive M7.7 flare, with Nobeyama Radioheliograph (NoRH) at 17 GHz. The is also observed by SDO/AIA in its passbands 94 131 Å\. In data, it revealed as overall arcade-like consisting several intensity enhancements bridged generally weak emissions,...
Abstract The origin of multiple peaks in light curves various wavelengths remains illusive during flares. Here we discuss the flare SOL2023-05-09T03:54M6.5 with six flux as recorded by a tandem new microwave and hard X-ray (HXR) instruments. According to its spectra, represents high-turnover-frequency (>15 GHz) event. rather-complete HXR spectral coverage provides rare opportunity uncover such an event together simultaneous EUV images. We concluded that (1) sources originates around top...
We report a Nobeyama Radioheliograph (NoRH) microwave observation of propagating features nonthermal emission in solar flare on 1999 August 28, an M2.8 event for the GOES soft X-ray class. The had very extended source (≈4.5 × 104 km) that was well resolved by NoRH, and it is confirmed to be magnetic loop comparison with photospheric field. In rising phase burst, gyrosynchrotron observed high-rate (10 images per second) NoRH propagate from one end other speed 6 103 km s-1. also found 9 s-1...
Gyrosynchrotron emission generated by non-thermal electrons in solar and stellar coronal flares can be efficiently modulated slow magnetoacoustic oscillations the flaring loops. The modulation mechanism is based upon perturbation of efficiency Razin suppression optically thin gyrosynchrotron emission. Modulation anti-phase with density wave. observed depth up to an order magnitude higher than wave amplitude. This effect more pronounced at lower frequencies. Observations spatial resolution,...
We present a numerical study of optically thick gyrosynchrotron emission produced by fast electrons with anisotropic pitch-angle distributions. The anisotropy is found to affect substantially both radiation spectra and polarization. harmonic nature becomes more pronounced for the case. effect entirely provided reduction self-absorption coefficient due anisotropy; thus, it essentially different from electron cyclotron maser emission, which wave amplification under negative absorption. paper...