A5046020771- Solar and Space Plasma Dynamics
- Ionosphere and magnetosphere dynamics
- RNA and protein synthesis mechanisms
- Earthquake Detection and Analysis
- Geomagnetism and Paleomagnetism Studies
- Fractal and DNA sequence analysis
- Gamma-ray bursts and supernovae
- Genomics and Phylogenetic Studies
- Machine Learning in Bioinformatics
- Astro and Planetary Science
- Laser-Plasma Interactions and Diagnostics
- Solar Radiation and Photovoltaics
- Gas Dynamics and Kinetic Theory
- Stellar, planetary, and galactic studies
- SARS-CoV-2 and COVID-19 Research
- Computational Fluid Dynamics and Aerodynamics
- Protein Structure and Dynamics
- Magnetic confinement fusion research
- High-pressure geophysics and materials
- Genetic diversity and population structure
- Viral gastroenteritis research and epidemiology
- Fluid Dynamics and Turbulent Flows
- Bacteriophages and microbial interactions
- Laser-induced spectroscopy and plasma
- GNSS positioning and interference
Bureau of Meteorology
2014-2023
The University of Sydney
2011-2021
Lear (United States)
2015
Université d'Orléans
2002-2008
Centre National de la Recherche Scientifique
2002-2008
Le Studium
2007
Troitsk Institute for Innovation and Fusion Research
1996-2006
Laboratoire de Chimie Physique et Microbiologie pour l'Environnement
2005
Institute of Terrestrial Magnetism Ionosphere and Radio Wave Propagation
1999-2004
Russian Academy of Sciences
1999
Whistler waves are an intrinsic feature of the oblique quasiperpendicular collisionless shock waves. For supercritical waves, ramp region, where abrupt increase magnetic field occurs, can be treated as a nonlinear whistler wave large amplitude. In addition, possess linear precursor. There exist two critical Mach numbers related to components wave, first is known number and second referred number. When Much exceeded, stationary train cannot stand ahead ramp. Above number, anymore within...
We derive kinematic properties for two recent solar coronal transient waves observed off the western limb with Atmospheric Imaging Assembly (AIA) onboard Solar Dynamics Observatory (SDO) mission. The occurred over $\sim10$-min intervals on consecutive days - June 12 and 13, 2010. For first time, off-limb are imaged a high 12-sec cadence, making possible detailed analysis of these transients in low corona between $\sim1.1$-2.0 radii ($R_{s}$). use observations 193 211 {\AA} AIA channels to...
A set of experimental data is presented for a high‐Mach‐number ( M f = 5) quasiperpendicular (θ Bn 81°) bow shock layer crossed by Cluster spacecraft on 24 January 2001 at 07:05–07:09 UT. The measurements magnetic field, spectra electric field fluctuations, and ion distributions reveal that the highly nonstationary. In particular, profiles measured aboard different differ considerably from each other. mean frequency downshifted waves observed upstream ramp oscillates with characteristic time...
Type III solar radio bursts are the Sun's most intense and frequent nonthermal emissions. They involve two critical problems in astrophysics, plasma physics, space physics: how collective processes produce radiation magnetic reconnection occurs changes energy into kinetic energy. Here events identified definitively Solar Dynamics Observatory UV-EUV data, with strong upward downward pairs of jets, current sheets, cusp-like geometries on top time-varying loops, outflows along open field lines....
Because of the rapidly increasing role technology, including complicated electronic systems, spacecraft, etc., modern society has become more vulnerable to a set extraterrestrial influences (space weather) and requires continuous observation forecasts space weather. The major weather events like solar flares coronal mass ejections are usually accompanied by radio bursts, which can be used for real‐time forecast. Coronal type III bursts produced near local electron plasma frequency its...
We present the first spectroscopic images of solar radio transients from prototype for Murchison Widefield Array (MWA), observed on 2010 March 27. Our observations span instantaneous frequency band 170.9-201.6 MHz. Though our observing period is characterized as a `low' to `medium' activity, one broadband emission feature and numerous short-lived, narrowband, non-thermal features are evident. data represent significant advance in low imaging, enabling us follow spatial, spectral, temporal...
Solar flares are extremely energetic phenomena in our System. Their impulsive, often drastic radiative increases, particular at short wavelengths, bring immediate impacts that motivate solar physics and space weather research to understand the point of being able forecast them. As data algorithms improve dramatically, questions must be asked concerning how well forecasting performs; crucially, we ask rigorously measure performance order critically gauge any improvements. Building upon...
Coronal mass ejections (CMEs) are thought to drive collisionless shocks in the solar corona, which turn have been shown capable of accelerating energetic particles (SEPs) minutes. It has notoriously difficult extract information about particle spectra due lack in-situ measurements. is possible, however, combine remote observations with data-driven models order deduce coronal shock properties relevant local acceleration SEPs and their heliospheric connectivity near-Earth space. We present...
Major space weather events such as solar flares and coronal mass ejections are usually accompanied by radio bursts, which can potentially be used for real-time forecasts. Type II bursts produced near the local plasma frequency its harmonic fast electrons accelerated a shock wave moving through corona wind with typical speed of ∼1000 km s−1. The have dynamic spectra gradually falling time durations several minutes. This Letter presents new method developed to detect type automatically...
The structural analysis of genomic DNA sequences is discussed in the framework spectral approach, which sufficiently universal due to reciprocal correspondence and mutual complementarity Fourier transform length scales. characteristics random same nucleotide composition possess property self-averaging for relatively short M≥100–300. Comparison with determines statistical significance features observed. Apart from traditional applications search hidden periodicities, methods are also...
The Sun's electron number density profile ne(r) is vital for solar physics but not well measured or understood within a few radii RS. Here, new technique extracts directly from coronal type III radio bursts 40 ≤ f 180 MHz. Unexpectedly, wind-like regions with ne ∝ (r − RS)−2 are quite common below 2RS, and IIIs often have closely linear 1/f t spectra. consistent the data simulations interpreted in terms of conical flow localized sources (e.g., UV funnels) close to photosphere. It wind...
Abstract Type II solar radio bursts are often indicators for impending space weather events at Earth. They consequences of shock waves driven by coronal mass ejections (CMEs) that move outward from the Sun. We simulate such type combining elaborate three‐dimensional (3‐D) magnetohydrodynamic (MHD) predictions realistic CMEs near Sun with an analytic kinetic radiation theory developed recently. The simulation approach includes reconstruction initial magnetic fields, dimensioning flux rope CME...
Abstract A workshop was recently held at Nagoya University (2017 October 31–November 2), sponsored by the Center for International Collaborative Research, Institute Space-Earth Environmental University, Japan, to quantitatively compare performance of today’s operational solar flare forecasting facilities. Building upon Paper I this series, in II we described participating methods latest comparison effort, evaluation methodology, and presented quantitative comparisons. In paper, focus on...
A crucial challenge to successful flare prediction is forecasting periods that transition between "flare-quiet" and "flare-active". Building on earlier studies in this series (Barnes et al. 2016; Leka 2019a,b) which we describe methodology, details, results of comparison efforts, focus here patterns forecast outcomes (success failure) over multi-day periods. novel analysis developed evaluate success the context catching first event flare-active periods, conversely, correctly predicting...
Abstract We have analyzed nucleotide polymorphism within a 5.3-kb region encompassing the functional Est-6 gene and ψEst-6 putative pseudogene in 28 strains of Drosophila melanogaster one D. simulans. Two divergent sequence types were detected, which are not perfectly associated with allozyme variation. The level variation (π) is very close 5′-flanking (0.0059) (0.0057), but significantly higher intergenic (0.0141) (0.0122). 3′-flanking intermediate (0.0083). These observations may reflect...
A numerical model for wave propagation in an unstable plasma with inhomogeneities is developed. This describes the linear interaction of Langmuir packets electron beam and takes into account angular diffusion vector due to scattering on small‐amplitude density fluctuations, as well suppression instability caused by removal from resonance particles during crossing perturbations relatively large amplitude. Using this model, evolution inhomogeneous plasmas studied. To analyze data obtained both...
Abstract. A new method for remote sensing of the quasiperpendicular part bow shock surface is presented. The based on analysis high frequency electric field fluctuations corresponding to Langmuir, upshifted, and downshifted oscillations in electron foreshock. Langmuir waves usually have maximum intensity at upstream boundary this region. All these are generated by energetic electrons accelerated zone front. Nonstationary behavior shock, particular due rippling, should result modulation...
In the present paper, Global Oscillation Network Group (GONG) solar magnetograms are used to automatically identify active regions by thresholding line‐of‐sight component of magnetic field. The flare potential is predicted locating strong‐gradient polarity inversion lines (SPILs) and estimating their parameters. parameters interest length SPIL, a proxy for its curvature; maximum west‐east south‐north gradients field in vicinity; sum gradients, summation being performed along SPIL. Analysis...
Type III radio bursts are produced near the local electron plasma frequency and/or its harmonic by fast electrons ejected from solar active regions and moving through corona wind. These have dynamic spectra with rapidly falling time. This paper presents two new methods developed to detect type automatically in data High Frequency Receiver (HFR) of STEREO/WAVES instrument onboard STEREO spacecraft. The first technique is applicable low‐frequency band (HFR‐1: 125 kHz 1.975 MHz) only. can...
Measurements performed aboard Cluster spacecraft near Earth's bow shock on 24 January 2001 provide convincing evidence of a loss‐cone feature within the electron foreshock region. This is formed by suprathermal electrons with energies 15–45 eV and pitch angles 130°–150° always accompanied electrostatic waves frequencies well below local plasma frequency. An instability analysis shows that these downshifted oscillations can result from cyclotron modes rather than beam as previously suggested.
This Letter presents the results of studies solar cycle variations occurrence rate coronal type III radio bursts. The spectra are provided by Learmonth Solar Radio Observatory (Western Australia), part USAF Telescope Network (RSTN). It is found that bursts strongly correlates with activity. However, profiles for smoothed burst differ considerably from those sunspot number, 10.7 cm flux, and flare index. (T3BOR) proposed as a new index T3BOR provides complementary information about activity...
Type II radio bursts are produced near the local plasma frequency fp and 2fp by shocks moving through corona solar wind. In present Letter eight well-defined coronal type (30-300 MHz) analyzed. Three results presented. First, it is found that dependence of central on time can be fitted to a power-law model, f ∝ (t − t0)−α, with 0.6 ⩽ α 1.3. Assuming constant shock velocity, these provide evidence density profile ne(r) in source regions closely resembles wind, r−2. One possible interpretation...
This Letter presents the first observations of a Rieger-type periodicity with period days in occurrence rate solar coronal type III radio bursts. The was detected during time interval from 2000 June 22 to 2003 December 31. partially contains maximum and declining phase cycle 23. spectra were provided by Learmonth Solar Radio Observatory Western Australia, part USAF Telescope Network.