Philippe-A. BourdinKarl-Franzens-Universität Graz | KFU Graz · Department of Geophysics, Astrophysics and Meteorology
Philippe-A. Bourdin
Dr. rer.-nat. (2014)
About
34
Publications
3,963
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448
Citations
Citations since 2016
Introduction
Philippe Bourdin currently works as a group leader in Computational Solar Physics at the Institute of Physics, University of Graz. His major topics are magneto-hydrodynamic simulations of the solar corona, and particle-kinetic simulations of magnetic reconnection, as well as in-situ observations of the electro-motive force during solar storms.
Additional affiliations
October 2020 - present
October 2013 - September 2020
January 2010 - September 2013
Max Planck Institute for Solar System Research, MPS
Position
- PhD Student
Description
- Stipend of the International Max Planck Research School, IMPRS
Education
April 2003 - March 2008
October 2000 - March 2003
Publications
Publications (34)
We conducted a high-resolution numerical simulation of the solar corona above a stable active region. The aim is to test the
field line braiding mechanism for a sufficient coronal energy input. We also check the applicability of scaling laws for coronal
loop properties like the temperature and density. Our 3D MHD model is driven from below by Hinod...
Context. We have conducted a 3D MHD simulation of the solar corona above an active region in full scale and high resolution, which shows coronal loops, and plasma flows within them, similar to observations.
Aims. We want to find the connection between the photospheric energy input by field-line braiding with the coronal energy conversion by Ohmic d...
Plasma beta is an important and fundamental physical quantity in order to understand plasma dynamics, particularly in the context of magnetically active stars, because it tells about the domination of magnetic versus thermodynamic processes on the plasma motion. We estimate the value ranges of plasma beta in different regions within the solar atmos...
Electromotive force is an essential quantity in dynamo theory. During a coronal mass ejection (CME), magnetic helicity gets decoupled from the Sun and advected into the heliosphere with the solar wind. Eventually, a heliospheric magnetic transient event might pass by a spacecraft, such as the Helios space observatories. Our aim is to investigate th...
Context. The structure and heating of coronal loops have been investigated for decades. Established scaling laws relate fundamental quantities like the loop apex temperature, pressure, length, and coronal heating.
Aims. We test these scaling laws against a large-scale 3D magneto-hydrodynamics (MHD) model of the solar corona, which became feasible w...
The European Solar Telescope (EST) is a project aimed at studying the magnetic connectivity of the solar atmosphere, from the deep photosphere to the upper chromosphere. Its design combines the knowledge and expertise gathered by the European solar physics community during the construction and operation of state-of-the-art solar telescopes operatin...
The ESA-JAXA BepiColombo mission will provide simultaneous measurements from two spacecraft, offering an unprecedented opportunity to investigate magnetospheric and exospheric dynamics at Mercury as well as their interactions with the solar wind, radiation, and interplanetary dust. Many scientific instruments onboard the two spacecraft will be comp...
The Pencil Code is a highly modular physics-oriented simulation code that can be adapted to a wide range of applications. It is primarily designed to solve partial differential equations (PDEs) of compressible hydrodynamics and has lots of add-ons ranging from astrophysical magnetohydrodynamics (MHD) to meteorological cloud microphysics and enginee...
The ESA-JAXA BepiColombo mission will provide simultaneous measurements from two spacecraft, offering an unprecedented opportunity to investigate magnetospheric and exospheric dynamics at Mercury as well as their interactions with the solar wind, radiation, and interplanetary dust. Many scientific instruments onboard the two spacecraft will be comp...
As we are heading toward the next solar cycle, presumably with a relatively small amplitude, it is of significant
interest to reconstruct and describe the past secular minima on the basis of actual observations at the time. The
Dalton Minimum is often considered one of the secular minima captured in the coverage of telescopic
observations. Neverthe...
As we are heading towards the next solar cycle, presumably with a relatively small amplitude, it is of significant interest to reconstruct and describe the past grand minima on the basis of actual observations of the time. The Dalton Minimum is often considered one of the grand minima captured in the coverage of telescopic observations. Nevertheles...
The quality of today's research is often tightly limited to the available computing power and scalability of codes to many processors. For example, tackling the problem of heating the solar corona requires a most realistic description of the plasma dynamics and the magnetic field. Numerically solving such a magneto-hydrodynamical (MHD) description...
We investigate the collective behaviour of particle orbits in the vicinity of magnetic reconnection in Earth's magneto-tail. Various regions of different kinds of orbital stability of particle motions are found. We locate regimes of temporary capture of particle orbits in configuration space as well as locations, where strong particle accelerations...
The quality of today's research is often tightly limited to the available computing power and scalability of codes to many processors. For example, tackling the problem of heating the solar corona requires a most realistic description of the plasma dynamics and the magnetic field. Numerically solving such a magneto-hydrodynamical (MHD) description...
We investigate the collective behavior of particle orbits in the vicinity of magnetic reconnection in Earth's magneto-tail. Various regions of different kinds of orbital stability of particle motions are found. We locate regimes of temporary capture of particle orbits in configuration space as well as locations, where strong particle accelerations...
The electromotive force (EMF) describes how the evolution and generation of a large-scale magnetic field is influenced by small-scale turbulence. Recent studies of in situ measurements have shown a significant peak in the EMF while a coronal mass ejection (CME) shock front passes by the spacecraft. The goal of this study is to use the EMF as an ind...
The electromotive force (EMF) describes how the evolution and generation of a large-scale magnetic field is influenced by small-scale turbulence. Recent studies of in-situ measurements have shown a significant peak in the EMF while a coronal mass ejection (CME) shock front passes by the spacecraft. The goal of this study is to use the EMF as an ind...
The emergence of dipolar magnetic features on the solar surface is an idealization. Most of the magnetic flux emergence occurs in complex multipolar regions. Here, we show that the surface pattern of magnetic structures alone can reveal the sign of the underlying magnetic helicity in the nearly force-free coronal regions above. The sign of the magn...
Solar and stellar dynamos shed small-scale and large-scale magnetic helicity of opposite signs. However, solar wind observations and simulations have shown that some distance above the dynamo both the small-scale and large-scale magnetic helicities have reversed signs. With realistic simulations of the solar corona above an active region now being...
Supporting Information S1
The Solar TErrestrial RElations Observatory (STEREO) and its heliospheric imagers (HI) have provided us the possibility to enhance our understanding of the interplanetary propagation of coronal mass ejections (CMEs). HI-based methods are able to forecast arrival times and speeds at any target and use the advantage of tracing a CME's path of propaga...
To understand the essential physics needed to reproduce magnetic reconnection events in 2.5-D particle-in-cell (PIC) simulations, we revisit the Geospace Environmental Modeling (GEM) setup. We set up a 2-D Harris current sheet (that also specifies the initial conditions) to evolve the reconnection of antiparallel magnetic fields. In contrast to the...
We investigate the combined effect of solar wind, Poynting-Robertson drag, and the frozen-in interplanetary magnetic field on the motion of charged dust grains in our solar system. For this reason we derive a secular theory of motion by the means of averaging method and validate it with numerical simulations of the un-averaged equations of motions....
The aim of this work is to investigate and characterise particle behaviour in
a (observationally-driven) 3D MHD model of the solar atmosphere above a slowly
evolving, non-flaring active region. We use a relativistic guiding-centre
particle code to investigate particle acceleration in a single snapshot of the
3D MHD simulation. Despite the lack of f...
Many applications in Solar physics need a 1D atmospheric model as initial condition or as reference for inversions of observational data. The VAL atmospheric models are based on observations and are widely used since decades. Complementary to that, the FAL models implement radiative hydrodynamics and showed the shortcomings of the VAL models since...
Context: The corona of the Sun can be observed since 1932 with instruments occulting the solar disc. Only few years later it became clear that the corona is way hotter than the visible solar surface and since then, the coronal heating mechanism is unclear. So far, many processes have been proposed that are able to deliver enough energy to the base...
Parameter and setup files used for a 3D-MHD simulation with the Pencil Code. The parameters are needed to reproduce the simulation, while the setup files show which modules of the Pencil Code were used to conduct the simulation.
The parameters file are in the state as used at the end of the simulation, when the analysis was performed. With the log...
Aims. The goal is to employ a 3D magnetohydro dynamics (MHD) model including spectral synthesis to model the corona in an observed solar active region. This will allow us to judge the merits of the coronal heating mechanism built into the 3D model.
Methods. Photospheric observations of the magnetic field and horizontal velocities in an active regio...
Reducing noise caused by the instrumentation in observational data is a
crucial step in data post-processing. A method is searched for that conserves
most of the instrumental resolution and introduces as few methodical artefacts
as possible. With such a method integrated in an observation sites software
tool-chain, the resources spent for the gener...
Analysing the measurement data of a complex system always means interpreting the data with respect to a certain model. For the interpretation of the reflectance spectra of human skin, we use a twofold model. Part one of the model relates mesoscopic quantities like concentrations of skin dyes and the scatterer size distribution to characteristic opti...
Projects
Projects (4)
We like to obtain the trajectories of charged particles due to the acceleration from electric fields. We run 3D MHD and 2.5D PIC simulations of Magnetic Reconnetion, e.g. in the Solar Corona or in the Heliosphere. This allows us to follow either one single test particle (from MHD data) or a statistical ensemble of test particles with the back-reaction to the fields (PIC models). Our goal is to study the dissipation of kinetic energy on the scales of electrons and ions
We develop a new method to automatically detect magnetic transient evens, such as inter-planetary CMEs in the heliosphere, and investigate how such events scale from the Sun to the orbits of the inner planets. Our new method allows to infer the sign of the magnetic helicity from single-points observations. Also we learn about MHD-turbulent processes such as the vorticity, the magnetic helicity, the current helicity, and the cross-helicity.
We aim to show how magnetic helicity is generated in, transported through, and decouples from the corona of the Sun and solar-like stars. In a first approach, we consider the locations of the sunspots to be a tracer for helicity generated inside the Sun by dynamo processes. Our current understanding indicates we may infer the sign of the helicity in the corona by the placement of sunspots. Later, helicity will decouple and be transported away with the solar wind, which requires reconnection and may explain why the sign of the helicity changes between the solar surface and when observed in the heliosphere.
