A5065772364- Solar and Space Plasma Dynamics
- Ionosphere and magnetosphere dynamics
- Astro and Planetary Science
- Stellar, planetary, and galactic studies
- Geomagnetism and Paleomagnetism Studies
- Geophysics and Gravity Measurements
- Solar Radiation and Photovoltaics
- Tropical and Extratropical Cyclones Research
- Magnetic confinement fusion research
- Planetary Science and Exploration
- Fluid Dynamics and Turbulent Flows
- Physics of Superconductivity and Magnetism
- Atmospheric Ozone and Climate
- Noncommutative and Quantum Gravity Theories
- Particle physics theoretical and experimental studies
- Algebraic and Geometric Analysis
- Atomic and Molecular Physics
- Quantum and electron transport phenomena
- Black Holes and Theoretical Physics
- Spacecraft Design and Technology
- Quantum and Classical Electrodynamics
- Earthquake Detection and Analysis
- Neutrino Physics Research
- Quantum, superfluid, helium dynamics
- Quantum Mechanics and Non-Hermitian Physics
Kiel University
2014-2023
Max Planck Institute for Solar System Research
2007-2020
Max Planck Society
2004-2018
Fachhochschule Kiel
2016-2018
Chinese Academy of Meteorological Sciences
2016
Chinese Academy of Sciences
2005-2016
Peking University
2001-2010
Planta Piloto de Procesos Industriales Microbiológicos
2010
Institute of Astronomy and Space Physics
2010
Planetary Science Institute
2010
Solar Orbiter, the first mission of ESA's Cosmic Vision 2015-2025 programme and a international collaboration between ESA NASA, will explore Sun heliosphere from close up out ecliptic plane. It was launched on 10 February 2020 04:03 UTC Cape Canaveral aims to address key questions solar heliospheric physics pertaining how creates controls Heliosphere, why activity changes with time. To answer these, carries six remote-sensing instruments observe corona, four in-situ measure wind, energetic...
A survey of solar wind three‐dimensional proton velocity distributions as measured by the Helios probes between 0.3 and 1 AU is presented. variety nonthermal features like temperature anisotropies, heat fluxes, or double streams has been observed. The relative speed second component increases on average with increasing decreasing heliocentric radial distance shows a correlation local Alfvén speed. marked anisotropy in core larger perpendicular than parallel to magnetic field ( T ∥ c < )...
Kinetic plasma physics of the solar corona and wind are reviewed with emphasis on theoretical understanding in situ measurements particles waves, as well remote-sensing observations made by means ultraviolet spectroscopy imaging. In order to explain coronal interplanetary heating, micro-physics dissipation various forms mechanical, electric magnetic energy at small scales (e.g., contained turbulences or non-uniform flows) must be addressed. We therefore scrutinise basic assumptions...
A survey of solar wind helium ion velocity distributions and derived parameters as measured by the Helios probes between 0.3 1 AU is presented. Nonthermal features like heat fluxes or He 2+ double streams temperature anisotropies have been frequently observed. Fairly isotropic only close to sector boundaries interplanetary magnetic field. At times in slow wind, persistent double‐humped constituting a anisotropy T ∥α / ⊥α > reliably identified. Distributions high‐speed generally small...
Observed electron distribution functions of the solar wind permanently exhibit three different components: a thermal core and suprathermal halo, which are always present at all pitch angles, sharply magnetic field aligned “strahl” is usually anti‐sunward moving. Whereas Coulomb collisions can explain relative isotropy population, origin halo more specifically its sunward directed part, remains unknown. In this study we radial evolution velocity in fast between 0.3 1.5 AU. For purpose combine...
Context. The Extreme Ultraviolet Imager (EUI) is part of the remote sensing instrument package ESA/NASA Solar Orbiter mission that will explore inner heliosphere and observe Sun from vantage points close to out ecliptic. advance “connection science” between solar activity heliosphere. Aims. With EUI we aim improve our understanding structure dynamics atmosphere, globally as well at high resolution, latitude perspectives. Methods. consists three telescopes, Full two High Resolution Imagers,...
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...
The magnetometer instrument on the Solar Orbiter mission is designed to measure magnetic field local spacecraft continuously for entire duration. need characterise not only background but also its variations scales from far above well below proton gyroscale result in challenging requirements stability, precision, and noise, as operational limitations both other instruments. vibration thermal environment has led significant development of mechanical sensor design. overall design, performance,...
The origin of the solar wind in coronal holes has long been unclear. We establish that starts flowing out corona at heights above photosphere between 5 megameters and 20 magnetic funnels. This result is obtained by a correlation Doppler-velocity radiance maps spectral lines emitted various ions with force-free field as extrapolated from photospheric magnetograms to different altitudes. Specifically, we find Ne7+ mostly radiate around megameters, where they have outflow speeds about 10...
Share Icon Twitter Facebook Reddit LinkedIn Reprints and Permissions Cite Search Site Citation Chuan‐Yi Tu, Eckart Marsch, Gary P. Zank; MHD Structures, Waves Turbulence in the Solar Wind: Observations Theories. Physics Today 1 July 1996; 49 (7): 64–66. https://doi.org/10.1063/1.2807697 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Dropdown Menu input auto suggest filter your All ContentPhysics Advanced
In order to address two of the principal scientific objectives Solar and Heliospheric Observatory (SOHO), studies heating mechanisms solar corona acceleration processes wind, we deduce electron temperatures, densities, ion velocities in plumes interplume regions polar coronal holes using ultraviolet observations from SUMER (Solar Ultraviolet Measurements Emitted Radiation) on SOHO. allows us study inner up a distance about 430,000 km above limb, or r = 1.6 R☉ (solar radius) center disk. We...
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...
The radial evolution of MHD turbulence in the inner heliosphere, as observed by Helios probes between 0.3 and 1 AU, is reanalyzed newly evaluated means Elsässer variables. It found that spectra energy outward ( e + ) inward − oriented fluctuations, cross helicity correlation related dimensionless ratios, like ones named after Alfvén or Elsässer, all undergo considerable with an overall trend for to steepen. These evolutionary tendencies are established both individual typical case studies a...
In order to explain the ion temperature anisotropies and differential speeds, as observed in solar wind high‐speed streams, a fluid type model is presented that takes into account heating acceleration by resonant wave‐particle interactions. Ion‐cyclotron fast magnetosonic waves propagating away from sun parallel interplanetary magnetic field are considered. The radial evolution of spectral wave energy density bi‐Maxwellian distributions calculated self‐consistently for spherically symmetric...
We report an analysis of the proton temperature anisotropy evolution from 0.3 to 2.5 AU based on Helios and Ulysses observations. With increasing distance fast wind data show a path in parameter space ( β ∥ p , T ⊥ / ). The first part trajectory is well described by anticorrelation between parallel beta, while after 1 with changes result agreement constraints derived fire hose instability. slow more irregular behavior, general it not possible recover single path. However, small temporal...
The fluctuating magnetic helicity is considered an important parameter in diagnosing the characteristic modes of solar wind turbulence. Among them Alfvén-cyclotron wave, which probably responsible for plasma heating, but has not yet been identified from Here, we present possible signatures waves distribution as a function θVB, angle between velocity and local mean field. We use field data STEREO spacecraft to calculate θVB normalized reduced σm. find dominant negative σm 1 s < p 4 (p time...
Magnetic field and plasma data collected by the Helios spacecraft between 0.3 1 AU near activity minimum of solar cycle 21 have been analyzed to establish spectral characteristics compressive fluctuations in inner wind their relation morphology flow magnetic field. The turbulence level is found be closely related stream structure or latitudinal location with respect heliospheric current sheet. Compressive low‐speed flows more fully developed intense. spectra are radially invariant come close...
A two‐component incompressible fluctuation model is presented to explain the radial evolution of solar wind fluctuations. The basic idea consider small‐scale fluctuations in as being composed Alfvén waves and convective structures. major are believed be created near coronal base propagate outward along magnetic field lines. structures defined variations perpendicular local direction. They either quasi‐static or turbulent slowly evolving plasma frame reference. connected, parallel direction,...