A5038006602- Astrophysics and Cosmic Phenomena
- Dark Matter and Cosmic Phenomena
- Particle physics theoretical and experimental studies
- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Neutrino Physics Research
- Astro and Planetary Science
- Gamma-ray bursts and supernovae
- Particle Detector Development and Performance
- Planetary Science and Exploration
- Radio Astronomy Observations and Technology
- High-Energy Particle Collisions Research
- Geomagnetism and Paleomagnetism Studies
- Quantum Chromodynamics and Particle Interactions
- Atmospheric Ozone and Climate
- Magnetic confinement fusion research
- Earthquake Detection and Analysis
- Astronomical Observations and Instrumentation
- Radiation Detection and Scintillator Technologies
- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Pulsars and Gravitational Waves Research
- SAS software applications and methods
- Particle Accelerators and Free-Electron Lasers
- Calibration and Measurement Techniques
Czech Academy of Sciences, Institute of Physics
2016-2025
University Hospital Hradec Králové
2023-2025
Charles University
2001-2025
Czech Academy of Sciences
2015-2024
Czech Academy of Sciences, Astronomical Institute
2013-2024
Universitat de Barcelona
2024
Institut d'Estudis Espacials de Catalunya
2024
LIP - Laboratory of Instrumentation and Experimental Particle Physics
2017-2023
Institute of Astronomy and Space Physics
2011-2023
Consejo Nacional de Investigaciones Científicas y Técnicas
2011-2023
We present a comparison between WIND/SWE observations (Kasper et al., 2006) of β ∥ p and T ⊥ / (where is the proton parallel beta are perpendicular temperatures, respectively; here indicate directions with respect to ambient magnetic field) predictions Vlasov linear theory. In slow solar wind, observed temperature anisotropy seems be constrained by oblique instabilities, mirror one fire hose, contrary results theory which predicts dominance cyclotron instability hose. The fast wind core...
We have performed a statistical study of substantial amount solar wind electron velocity distribution functions (eVDFs). In our data set, we combine measurements acquired onboard three spacecrafts (Helios, Cluster II, and Ulysses) in the low ecliptic latitudes covering heliocentric distance from 0.3 up to 4 AU. this study, focus on nonthermal properties measured eVDFs both slow fast regimes. The aim present is (1) provide, for first time, an analytical model fit separately all components...
Solar wind energy transfer to planetary magnetospheres and ionospheres is controlled by magnetic reconnection, a process that determines the degree of connectivity between interplanetary field (IMF) planet's field. During MESSENGER's second flyby Mercury, steady southward IMF was observed magnetopause threaded strong field, indicating reconnection rate ~10 times typical at Earth. Moreover, large flux event in magnetosheath, plasmoid multiple traveling compression regions were Mercury's...
We have performed a statistical study of substantial amount electron data acquired in the solar wind to understand constraints on temperature anisotropy by plasma instabilities and Coulomb collisions. use large set measurements from three different spacecraft (Helios I, Cluster II, Ulysses) collected low ecliptic latitudes covering radial distance Sun 0.3 up 4 AU. estimate using fits measured velocity distribution functions situ. two population (core halo) analytical model properties both...
During MESSENGER's third flyby of Mercury, the magnetic field in planet's tail increased by factors 2 to 3.5 over intervals 3 minutes. Magnetospheric substorms at Earth are powered similar loading, but amplitude is lower a factor approximately 10 and typical durations 1 hour. The extreme loading observed Mercury implies that relative intensity must be much larger than Earth. correspondence between duration enhancements characteristic time for Dungey cycle, which describes plasma circulation...
Observations by MESSENGER show that Mercury's magnetosphere is immersed in a comet-like cloud of planetary ions. The most abundant, Na+, broadly distributed but exhibits flux maxima the magnetosheath, where local plasma flow speed high, and near spacecraft's closest approach, atmospheric density should peak. magnetic field showed reconnection signatures form transfer events, azimuthal rotations consistent with Kelvin-Helmholtz waves along magnetopause, extensive ultralow-frequency wave...
Mercury's regolith, derived from the crustal bedrock, has been altered by a set of space weathering processes. Before we can interpret composition, it is necessary to understand nature these surface alterations. The processes that weather are same as those form exosphere (micrometeoroid flux and solar wind interactions) moderated local environment presence global magnetic field. To comprehend how acts on an understanding needed contributing act interactive system. As no direct information...
The Radio and Plasma Waves (RPW) instrument on the ESA Solar Orbiter mission is described in this paper. This designed to measure in-situ magnetic electric fields waves from continuous a few hundreds of kHz. RPW will also observe solar radio emissions up 16 MHz. primary importance science requirements since it essential answer three four overarching objectives. In addition exchange on-board data with other instruments order process algorithms for interplanetary shocks type III langmuir detections.
The proton thermal energetics in the slow solar wind between 0.3 and 1 AU is reinvestigated using Helios 2 data, complementing a similar analysis for fast [Hellinger et al., 2011]. results winds are compared discussed context of previous results. Protons need to be heated perpendicular direction with respect ambient magnetic field from AU. In parallel direction, protons cooled at AU, cooling rate comparable corresponding heating rate; required decreases until transition occurs: by require...
[1] The proton thermal energetics in the fast solar wind between 0.3 and 1 AU is reinvestigated using Helios 2 data. Closer to Sun, it estimated that, account for observed radial profiles of parallel perpendicular temperature, nonnegligible cooling heating are necessary. Around needed both directions. We also calculate corresponding rates find that total significant interplanetary necessary, agreement with previous results. possible influence deceleration streams due interaction slow ones...
Abstract. The Whisper instrument yields two data sets: (i) the electron density determined via relaxation sounder, and (ii) spectrum of natural plasma emissions in frequency band 2–80 kHz. Both sets allow for three-dimensional exploration magnetosphere by Cluster mission. total can be derived unambiguously sounder most magnetospheric regions, provided it is range 0.25 to 80 cm-3 . already observed earlier spacecraft are fairly well measured instrument, thanks digital technology which largely...
The first (M1), second (M2), and third (M3) MESSENGER flybys of Mercury traversed the planet's magnetotail from 1.25 to 3.25 R M downstream planet, where is Mercury's radius (2440 km). encounters took place under northward, southward, variable‐polarity interplanetary magnetic field (IMF), respectively. strength B in follows a power law decrease with increasing antisunward distance ∣ X ∣, ∼ G , varying −5.4 for northward −1.6 southward IMF. Low‐latitude boundary layers (LLBLs) containing...
Oblique fire hose instability is investigated using hybrid simulations for proton betas of the order one and parallel temperatures sufficiently greater than perpendicular ones. The confirm previous simulation results showing that this has self‐destructing properties efficiently reduces temperature anisotropy. A parametric study one‐dimensional standard shows stronger changes in anisotropy wave emissions appear larger initial anisotropies. An ideal, slow plasma expansion, modeled by a...
Two‐dimensional particle‐in‐cell (PIC) simulations are used for analyzing in detail different nonstationary behaviors of a perpendicular supercritical shock. A recent study by Hellinger et al. (2007) has shown that the front shock can be dominated emission large‐amplitude whistler waves. These waves inhibit self‐reformation driven reflected ions; then, appears almost “quasi‐stationary.” The present stresses new complementary results. First, fixed β i value, (WWE) persists high M above...
Six flux transfer events (FTEs) were encountered during MESSENGER's first two flybys of Mercury (M1 and M2). For M1 the interplanetary magnetic field (IMF) was predominantly northward four FTEs with durations 1 to 6 s observed in magnetosheath following southward IMF turnings. The steadily M2, an FTE 4 duration just inside dawn magnetopause followed ∼32 later by a 7‐s magnetosheath. Flux rope models fit data determine dimensions content. largest MESSENGER had diameter ∼1 R M (where is...
Nonlinear properties of the oblique resonant electron fire hose instability are investigated using two‐dimensional particle‐in‐cell simulations in Darwin approximation for weak initial growth rates. The has a self‐destructive nonlinear behavior; it destabilizes nonpropagating branch which only exists sufficiently strong temperature anisotropy. evolution leads to generation waves turn scatter electrons and reduce their As anisotropy is being reduced, disappears generated standing transformed...
Abstract We present an observational analysis of electron cooling/heating rates in the fast and slow solar wind between 0.3 1 AU. fit velocity distribution functions acquired situ by Helios 2 spacecraft a three‐component (core‐halo‐strahl) analytical model. The resulting radial profiles macroscopic characteristics (density, temperatures, heat fluxes) are employed to examine properties theoretical energy balance equations estimate external terms. Our indicates that contrast protons electrons...
We use the plasma density based on measurements of probe-to-spacecraft potential in combination with magnetic field by MAG to study fields and fluctuations solar wind observed Solar Orbiter during first perihelion encounter ($\sim$0.5~AU away from Sun). In particular we polarization wave field, phase between compressible compressibility ratio (the normalized B) characterize waves turbulence. find that are out-of-phase component for intervals turbulence, while they circular-polarized around...
Data from multiple experiments suggest that the current interaction models used in Monte Carlo simulations do not correctly reproduce hadronic interactions air showers produced by ultra-high-energy cosmic rays (UHECR). We have created a large library of UHECR where at highest energies are slightly modified various ways - but always within constraints accelerator data, without any abrupt changes with energy and assuming specific mechanism or dramatically new physics ultra-high energies....