
Olga V. KhabarovaTel Aviv University | TAU · Faculty of Exact Sciences
Olga V. Khabarova
PhD
About
110
Publications
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Introduction
Olga does research in Space Physics and Environmental Science. Current projects: https://www.spaceweather.sites.tau.ac.il/ , https://csdb.izmiran.ru/.
Additional affiliations
February 2020 - present
April 2010 - present
February 2004 - February 2010
Education
September 1990 - February 1997
Publications
Publications (110)
Remote sensing techniques provide crucial insights into ancient settlement patterns in various regions by uncovering previously unknown archaeological sites and clarifying the topological features of known ones. Meanwhile, in the northern part of the Southern Levant, megalithic structures remain largely underexplored with these methods. This study...
Supplementary material:
Khabarova O., Price C. (2024) Importance and challenges of geomagnetic storm forecasting, Frontiers in Astronomy and Space Sciences, 11, 1493917, https://doi.org/10.3389/fspas.2024.1493917
The study aims to understand the role of solar wind current sheets (CSs) in shaping the spectrum of turbulent fluctuations and driving dissipation processes in space plasma. Local non-adiabatic heating and acceleration of charged particles in the solar wind is one of the most intriguing challenges in space physics. Leading theories attribute these...
Space weather prediction is a central focus of solar-terrestrial studies, with forecasts of geomagnetic storms deemed critical due to their significant practical implications. We have gathered facts that highlight the effects of geomagnetic storms on electric power systems and satellites. Recent studies indicate that geomagnetic storms of moderate...
Recent studies demonstrate the effectiveness of integrated archaeogeophysical tools in resolving various geological-environmental challenges. This fact involves combining geophysical methods in archaeological fieldwork or remote sensing methods for preliminary survey and analysis of archaeological sites, potentially enhanced by machine learning tec...
Leukemia is the most common cancer in children. Its incidence has been increasing worldwide since 1910th, suggesting the presence of common sources of the disease, most likely related to people’s lifestyle and environment. Understanding the relationship between childhood leukemia and environmental conditions is critical to preventing the disease. T...
The modern state of Israel is located between 29^o and 33^o north of the Earth’s equator. It is a small (about 22,000 km^2) subtropical region between the temperate and tropical zones, characterized chiefly by semi-arid and arid climates. Such climate causes increased productivity and water-use efficiency due to elevated CO_2, which tends to increa...
The study is devoted to the Comparison of the characteristics of the spectra of the interplanetary magnetic field turbulent fluctuations with the number of current sheets over a long interval containing different types of solar wind, including ICME and Sheath region. The study is important for understanding the role of current sheets, regularly obs...
Boundary current sheets (CSs) can be formed in collisionless space plasmas in the environment of exoplanets and cold stars. Usually they represent curved surfaces carrying the electric current analogous to the well-known planetary ionospheres, magnetopauses, or stellar coronas surrounding celestial bodies. At smaller local scales, some of them can...
The heliospheric current sheet (HCS) is considered as a tangential discontinuity in many solar wind models. However, there is evidence for the existence of closed magnetic field lines near the HCS. If this is the case, there is a problem of excessive accumulation of plasma moving along magnetic field lines into the HCS that should make the HCS unst...
Current sheets (CSs) are preferred sites of magnetic reconnection and energy dissipation in astrophysical plasmas. Electric currents in them may be carried by both electrons and ions. In our prior theoretical studies of the CS formation in turbulent plasmas, we utilized fully kinetic and hybrid code simulations with ions considered as particles and...
In October 2017, the Scientific Committee on Solar-Terrestrial Physics (SCOSTEP) Bureau established a committee for the design of SCOSTEP's Next Scientific Programme (NSP). The NSP committee members and authors of this paper decided from the very beginning of their deliberations that the predictability of the Sun–Earth System from a few hours to ce...
Current sheets (CSs) are preferred sites of magnetic reconnection and energy dissipation in turbulent collisionless astrophysical plasmas. In our prior theoretical studies of processes associated with the CS formation in turbulent plasmas, for which we utilized fully kinetic and hybrid code simulations with ions considered as particles and electron...
We propose a new method of the automated identification of current sheets (CSs) that represents a formalization of the visual inspection approach employed in case studies. CSs are often identified by eye via the analysis of characteristic changes in the interplanetary magnetic field (IMF) and plasma parameters. Known visual and semi‐automated empir...
Recent accumulation of a critical mass of observational material from different spacecraft complete with the enhanced abilities of numerical methods have led to a boom of studies revealing the high complexity of processes occurring in the heliosphere. Views on the solar wind filling the interplanetary medium have dramatically developed from the beg...
Our understanding of processes occurring in the heliosphere historically began with reduced dimensionality - one-dimensional (1D) and two-dimensional (2D) sketches and models, which aimed to illustrate views on large-scale structures in the solar wind. However, any reduced dimensionality vision of the heliosphere limits the possible interpretations...
In October 2017, the Scientific Committee on Solar-Terrestrial Physics (SCOSTEP) Bureau established a committee for the design of SCOSTEP's Next Scientific Program (NSP). The NSP committee members and authors of this paper, decided from the very beginning of their deliberations that the predictability of the Sun-Earth System from a few hours to cen...
Our understanding of processes occurring in the heliosphere historically began with reduced dimensionality - one-dimensional (1D) and two-dimensional (2D) sketches and models, which aimed to illustrate views on large-scale structures in the solar wind. However, any reduced dimensionality vision of the heliosphere limits the possible interpretations...
(Published in JGR, 2021: https://doi.org/10.1029/2020JA029099).
We propose a new method of the automated identification of current sheets (CSs) that represents a formalization of the visual inspection approach employed in case studies. CSs are often identified by eye via the analysis of characteristic changes in the interplanetary magnetic field (I...
When spacecraft cross the heliospheric plasma sheet (HPS) that separates large-scale magnetic sectors of opposite directions in the solar wind, multiple rapid fluctuations in the sign of the magnetic radial component are often observed. These fluctuations indicate the change of the sign of the azimuth electric current density within the HPS. Possib...
A new telegrapher-type Parker transport equation was derived from the existing underlying focused transport equation to model the acceleration of energetic particles by contracting and reconnecting small-scale magnetic flux ropes (SMFRs) in the large-scale solar wind. Time-dependent and steady-state analytical solutions were found that unify all SM...
Suprathermal electrons with energies of ~70eV and above are observed at 1 AU as dispersionless halo electrons and magnetic field-aligned beams of strahls. For a long time, it has been thought that the both populations originate only from the solar corona, and the only active process impacting their properties in the solar wind is scattering. This v...
We suggest a solution of the problem of the description of magnetic and electric fields occurring during large-scale nonradiative processes in the collisionless space plasma. The key idea is that the quasineutrality condition and the field-aligned force equilibrium of electrons should be taken into account. Equations describing the plasma are divid...
We develop an axisymmetric numerical MHD model that allows us to investigate the spatial characteristics of the interplanetary magnetic field (IMF) and key solar wind plasma parameters from 20 to 400 solar radii over all heliolatitudes. The study is aimed at an analysis of the evolution of the spatial structure of the heliosphere through the solar...
New analytical steady-state and time-dependent solutions for the acceleration of energetic particles by contracting
and reconnecting small-scale flux ropes (SMFRs) in the solar wind are presented. For this purpose, a telegrapher type Parker transport equation was derived from the existing underlying focused transport equation. The solutions unify a...
Recent studies of particle acceleration in the heliosphere have revealed a new mechanism that can locally energize particles up to several MeV nucleon–1. Stream–stream interactions, as well as the heliospheric current sheet (CS)—stream interactions, lead to formation of large magnetic cavities, bordered by strong CSs, which in turn produce secondar...
In this study we use theoretical concepts and computational-diagnostic tools of Tsallis non-extensive statistical theory (Tsallis q-triplet: qsen, qrel, qstat), complemented by other known tools of nonlinear dynamics such as Correlation Dimension and surrogate data, Hurst exponent, Flatness coefficient, and p-modeling of multifractality, in order t...
A stationary axisymmetric MHD model of the solar wind has been constructed, which allows us to study the spatial distribution of the magnetic field and plasma characteristics at radial distances from 20 to 400 radii of the Sun at almost all heliolatitudes. The model takes into account the changes in the magnetic field of the Sun during a quarter of...
The solar magnetic field (SMF) has historically been considered as dipole in order to build models of the radially expanding corona, that is, the solar wind in the solar minimum. The simplified approach suggests the existence of only one quasi-stationary current sheet (QCS) of solar origin in the heliosphere, namely, the heliospheric current sheet...
Recent studies of unusual or atypical energetic particle flux events (AEPEs) observed at 1 au show that another mechanism, different from diffusive shock acceleration, can energize particles locally in the solar wind. The mechanism proposed by Zank et al. is based on the stochastic energization of charged particles in regions filled with numerous s...
Crossings of the heliospheric current sheet (HCS) at the Earth’s orbit are often associated with observations of anisotropic beams of energetic protons accelerated to energies from hundreds of keV to several MeV and above. A connection between this phenomenon and the occurrence of small-scale magnetic islands (SMIs) near reconnecting current sheets...
Within the self-consistent hybrid model based on the quasi-adiabatic approximation of the proton dynamics, a fine structure of strong current sheets (SCSs) in the solar wind has been investigated, including the heliospheric current sheet. The motion of electrons is fast and considered in the Boltzmann approximation. The simulation results have been...
Within the axisymmetric MHD model of the solar wind, the magnetic field of the Sun has been analyzed in two phases of the solar cycle: the minimum activity, when the dipole magnetic field dominates and the maximum activity, when the quadrupole field predominates. It has been shown that during the period of maximum solar activity, the heliospheric c...
Our previous kinetic transport theoretical development for energetic particle acceleration by and large-scale transport through solar wind regions with numerous dynamic small-scale flux ropes in the strong guide/background field limit is further analyzed and extended. The basic flux-rope acceleration mechanisms and the issue of compressibility are...
Previous application of our focused transport equation for energetic ion test particle acceleration by numerous active small-scale flux ropes to solar wind conditions near 1 au yielded the formation of hard power-law spectra with high particle pressure. We present an extended theory where the focused transport equation is coupled to a new MHD turbu...
The possibility that charged particles are accelerated statistically in a "sea" of small-scale interacting magnetic flux ropes in the supersonic solar wind is gaining credence. In this Letter, we extend the Zank et al. statistical transport theory for a nearly isotopic particle distribution by including an escape term corresponding to particle loss...
An extensive analysis of Ulysses observations of the solar wind speed V from 1990 to 2008 is under-taken. It is shown that the evolution of V with heliocentric distance r depends substantially on both the heliolatitude and the solar activity cycle. Deviations from the predicted Parker's profile of V(r) are so considerable that cannot be explained b...
In Russian. For the English version, please see https://www.researchgate.net/publication/325986194_Evolution_of_the_solar_wind_speed_with_heliocentric_distance_and_solar_cycle_Surprises_from_Ulysses_and_unexpectedness_from_observations_of_the_solar_corona
Представлены результаты наблюдений космического аппарата Ulysses за весь период стабильных изм...
We present the analysis of Ulysses observations of the solar wind speed (V) from 1990 to 2008. We show that the evolution of V with heliocentric distance (r) depends on both the heliolatitude and the solar activity cycle substantially. Deviations from the predicted Parker's profile of V(r) are so considerable that cannot be explained by scarcity of...
A constant improvement of geomagnetic storm prediction techniques represents one of key tasks of the solar-terrestrial physics. The biggest problem of space weather predictions is that most prognoses can produce an alert just ~40 minutes in advance of a geomagnetic storm commencement; therefore there is no time to implement space weather counter-me...
Case studies show that some energetic particle flux enhancements up to MeV/nuc. observed at 1 AU cannot be treated as a consequence of particle acceleration at shocks or during flares. Atypical energetic particle events (AEPEs) are often detected during crossings of magnetic cavities formed by strong current sheets of various origins in the solar w...
We provide evidence for particle acceleration up to ~5 MeV at reconnecting current sheets in the solar wind based on both case studies and a statistical analysis of the energetic ion and electron flux data from the five Advanced Composition Explorer Electron, Proton, and Alpha Monitor (EPAM) detectors. The case study of a typical reconnection exhau...
We provide observational evidence for the existence of large-scale cylindrical (or conic-like) current sheets (CCSs) at high heliolatitudes. Long-lived CCSs were detected by Ulysses during its passages over the South Solar Pole in 1994 and 2007. The characteristic scale of these tornado-like structures is several times less than a typical width of...
The occurrence of unusual energetic particle enhancements up to several MeV/nuc at leading edges of corotating interaction regions (CIRs), near the heliospheric current sheet and downstream of interplanetary shocks at 1AU has puzzled observers for a long time. Commonly accepted mechanisms of particle energization, such as a classical diffusive shoc...
We investigate quasi-adiabatic dynamics of charged particles in strong current sheets (SCSs) in the solar wind, including the heliospheric current sheet (HCS), both theoretically and observationally. A self-consistent hybrid model of an SCS is developed in which ion dynamics is described at the quasi-adiabatic approximation, while the electrons are...
The self-consistent 1D kinetic Harris-like model of a collisionless current sheet is developed for the case of the current sheet experiencing the impact of an external uniform gravity field. The ambipolar Pannekoek-Rosseland electric field appears in the system as a result of the additional drift motion of ions and electrons. This produces separati...
We explore the role of heliospheric magnetic field configurations and conditions that favor the generation and confinement of small-scale magnetic islands associated with atypical energetic particle events (AEPEs) in the solar wind. Some AEPEs do not align with standard particle acceleration mechanisms, such as flare-related or simple diffusive shock a...
Computational and observational evidence is accruing that heliospheric shocks, as emitters of vorticity, can produce downstream magnetic flux ropes and filaments. This led Zank et al. to investigate a new paradigm whereby energetic particle acceleration near shocks is a combination of diffusive shock acceleration (DSA) with downstream acceleration...
An emerging paradigm for the dissipation of magnetic turbulence in the supersonic solar wind is via localized quasi-2D small-scale magnetic island
reconnection processes. An advection-diffusion transport equation for a nearly isotropic particle distribution describes particle transport and energization in a region of interacting magnetic islands [1...
Shock waves, as shown by simulations and observations, can generate high levels of downstream vortical turbulence, including magnetic islands. We consider a combination of diffusive shock acceleration (DSA) and downstream magnetic-island-reconnection-related processes as an energization mechanism for charged particles. Observations of electron and...
We develop a single-fluid 2-D analytical model of the axially symmetric thin heliospheric current sheet (HCS) embedded into the heliospheric plasma sheet (HPS). A HCS-HPS system has a shape of a relatively thin plasma disk limited by separatrices that also represent current sheets, which is in agreement with Ulysses observations in the aphelion, wh...
We consider different limits of our recently developed kinetic transport theory to investigate the potential of supersonic solar wind regions containing several small-scale flux ropes to explain the acceleration of suprathermal ions to power-law spectra as observations show. Particle acceleration is modeled in response to flux-rope activity involvi...
As a consequence of the evolutionary conditions [28; 29], shock waves can generate high levels of downstream vortical turbulence. Simulations [32-34] and observations [30; 31] support the idea that downstream magnetic islands (also called plasmoids or flux ropes) result from the interaction of shocks with upstream turbulence. Zank et al. [18] specu...
We present observations of energetic particle flux increases up to 1 MeV at 1 AU,
which cannot be associated with ordinary mechanisms of particle acceleration, such as
acceleration at shocks or at the Sun. Such unusual energetic particle events very likely have a
local origin. Multi-spacecraft observations show that numerous cases of energetic part...
We performed an empirical investigation of forest growth for two types of forests in northern Eurasia (larches and spruces) in order to show that the sensitivity of trees to the variable climate and geomagnetic field can be seen even under the large-scale average. The main purpose of this research was to model a forest growth rate V for each forest...
Increases of ion fluxes in the keV-MeV range are sometimes observed near the
heliospheric current sheet (HCS) during periods when other sources are absent.
These resemble solar energetic particle (SEP) events, but the events are weaker
and apparently local. Conventional explanations based on either shock
acceleration of charged particles or particl...
Particles of fast solar wind in the vicinity of the heliospheric current sheet
(HCS) or in a front of interplanetary coronal mass ejections (ICMEs) often
reveal very peculiar energy or velocity profiles, density distributions with
double or triple peaks, and well-defined streams of electrons occurring around
or far away from these events. In order...
Simulations of particle acceleration in turbulent plasma regions with multiple contracting and merging (reconnecting) magnetic islands emphasize the key role of temporary particle trapping in island structures for the efficient acceleration of particles to form hard power-law spectra. Statistical kinetic transport theories have been developed that...
We study the angular distribution of the solar wind magnetic field vector at 1 AU and its solar cycle dependence using ACE observations. A total of twelve 27.27 day (the duration of a solar rotation) intervals during the solar maximum, the solar minimum, as well as the ascending and descending phases of solar cycle 23 are examined. For all selected...
An emerging paradigm for the dissipation of magnetic turbulence in the supersonic solar wind is via localized small- scale reconnection processes, essentially between quasi-2D interacting magnetic islands. Charged particles trapped in merging magnetic islands can be accelerated by the electric field generated by magnetic island merging and the cont...