Simulating the FIP effect in coronal loops using a multi-species kinetic-fluid model

2021 ◽  
Author(s):  
Nicolas Poirier ◽  
Michael Lavarra ◽  
Alexis Rouillard ◽  
Mikel Indurain ◽  
Pierre-Louis Blelly ◽  
...  
Keyword(s):  
Heavy Ions ◽  
Coronal Loop ◽  
Ponderomotive Force ◽  
Fluid Model ◽  
Charged Particles ◽  
Atmospheric Model ◽  
Coronal Loops ◽  
Composition Distribution ◽  
Collision Processes ◽  
First Ionization Potential

<p>We investigate abundance variations of heavy ions in coronal loops. We develop and exploit a multi-species model of the solar atmosphere (called <em>IRAP’s Solar Atmospheric Model</em>: <em>ISAM</em>) that solves for the transport of neutral and charged particles from the chromosphere to the corona. We investigate the effect of different mechanisms that could produce the First Ionization Potential (FIP) effect. We compare the effects of the thermal force and of the ponderomotive force. The propagation, reflection and dissipation of Alfvén waves is solved using two distinct models, the first one from <em>Chandran et al. (2011)</em> and the second one that is a more sophisticated turbulence model called <em>Shell-ATM</em>. <em>ISAM</em> solves a set of 16-moment transport equations for both neutrals and charged particles. Protons and heavy ions are heated by Alfvén waves, which then heat up the electrons via collision processes. We show preliminary results on composition distribution along a typical coronal loop and compare with typical FIP biases. This work was funded by the European Research Council through the project SLOW_SOURCE - DLV-819189.</p>

Study of ion separation mechanism in the multi-component vacuum arc discharge

2021 ◽  
Author(s):  
Qiang Sun ◽  
Qianhong Zhou ◽  
Hantian Zhang ◽  
Wei Yang ◽  
Ye Dong ◽  
...  
Keyword(s):  
Heavy Ions ◽  
Cathode Spot ◽  
Arc Discharge ◽  
Fluid Model ◽  
Composite Cathode ◽  
Plasma Jets ◽  
Vacuum Arc ◽  
Separation Mechanism ◽  
Ion Separation ◽  
Light Ions

Abstract The separation phenomenon of light and heavy ions was widely observed experimentally in the vacuum arc discharge with multi-component composite cathode. In this work, a two-dimensional axisymmetric multi-fluid model is used to study the separation mechanism in the multi-component composite cathode vacuum arc. The multi-component vacuum arcs are simulated as a whole which includes separate cathode spot jets, the mixing region, and common arc column. The results show that the plasma jets originated from the separate cathode spot mix together to form a common arc column after a certain distance from the cathode. Due to the rapid increase of ion temperature dozens of times in mixing region of cathode spot jet, the effect of pressure gradient becomes far greater than that of the collisions between light and heavy ions. This leads to a shift in the predominant ion motion mechanism from ion-ion collision (single cathode spot jet region) to pressure expansion (the mixing region). Finally, the light ions gain higher velocities under pressure expansion. In addition, the effect of thermal conductivity and viscosity leads to the wider high temperature regions for light ions, thus making a wider distribution of corresponding ion flux. The numerical results are qualitatively consistent with the experimental results. This paper provides an insight into ion separation mechanism in the multi-component vacuum arc.

scholarly journals Three-dimensional multi-fluid model of a coronal streamer belt with a tilted magnetic dipole

2015 ◽  
Vol 33 (1) ◽  
pp. 47-53 ◽  
Author(s):  
L. Ofman ◽  
E. Provornikova ◽  
L. Abbo ◽  
S. Giordano
Keyword(s):  
Solar Wind ◽  
Heavy Ions ◽  
Fluid Model ◽  
Slow Solar Wind ◽  
Streamer Belt ◽  
Lower Corona ◽  
Adequate Model ◽  
Coronal Streamer ◽  
Ion Emission ◽  
D Model

Abstract. Observations of streamers in extreme ultraviolet (EUV) emission with SOHO/UVCS show dramatic differences in line profiles and latitudinal variations in heavy ion emission compared to hydrogen Ly-α emission. In order to use ion emission observations of streamers as the diagnostics of the slow solar wind properties, an adequate model of a streamer including heavy ions is required. We extended a previous 2.5-D multi-species magnetohydrodynamics (MHD) model of a coronal streamer to 3-D spherical geometry, and in the first approach we consider a tilted dipole configuration of the solar magnetic field. The aim of the present study is to test the 3-D results by comparing to previous 2.5-D model result for a 3-D case with moderate departure from azimuthal symmetry. The model includes O5+ ions with preferential empirical heating and allows for calculation of their density, velocity and temperature in coronal streamers. We present the first results of our 3-D multi-fluid model showing the parameters of protons, electrons and heavy ions (O5+) at the steady-state solar corona with a tilted steamer belt. We find that the 3-D results are in qualitative agreement with our previous 2.5-D model, and show longitudinal variation in the variables in accordance with the tilted streamer belt structure. Properties of heavy coronal ions obtained from the 3-D model together with EUV spectroscopic observations of streamers will help understanding the 3-D structures of streamers reducing line-of-sight integration ambiguities and identifying the sources of the slow solar wind in the lower corona. This leads to improved understanding of the physics of the slow solar wind.

scholarly journals Observation and simulation of a filament eruption associated with the contraction of the overlying coronal loops and the filament rotation

2013 ◽  
Vol 8 (S300) ◽  
pp. 504-506
Author(s):  
X. L. Yan ◽  
Z. K. Xue ◽  
Z. X. Mei
Keyword(s):  
Coronal Loop ◽  
Coronal Loops ◽  
Solar Dynamics Observatory ◽  
Filament Eruption ◽  
Solar Dynamics ◽  
Rotation Motion

AbstractBy using the data of Solar Dynamics Observatory (SDO), we present a case study of the contraction of the overlying coronal loop and the rotation motion of a sigmoid filament on 2012 May 22. At the beginning of the filament eruption, the overlying coronal loop experienced a significant contraction. In the following, the filament started to rotate counterclockwise. We also carried the simulation to investigate the process of the filament eruption.

scholarly journals Signatures of red-shifted footpoints in the quiescent coronal loop system

2019 ◽  
Author(s):  
Yamini K. Rao ◽  
Abhishek K. Srivastava ◽  
Pradeep Kayshap ◽  
Bhola N. Dwivedi
Keyword(s):  
Spectral Data ◽  
Coronal Loop ◽  
Doppler Velocity ◽  
Coronal Loops ◽  
Solar Dynamics Observatory ◽  
Heating Mechanism ◽  
Multi Wavelength ◽  
Solar Dynamics ◽  
Impulsive Heating ◽  
Imaging Spectrograph

Abstract. We observed quiescent coronal loops using multi-wavelength observations from the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) on 2016 April 13. The flows at the footpoints of such loop systems are studied using spectral data from Interface Region Imaging Spectrograph (IRIS). The Doppler velocity distributions at the footpoints lying in the moss region show the negligible or small flows at Ni I, Mg II k3 and C II line corresponding to upper photospheric and chromospheric emissions. Significant red-shifts (downflows) ranging from (1 to 7) km s−1 are observed at Si IV (1393.78 Å; log(T/K) = 4.8) which is found to be consistent with the existing results regarding dynamical loop systems and moss regions. Such downflows agree well with the impulsive heating mechanism reported earlier.

scholarly journals Coronal global EIT waves as tools for multiple diagnostics

2007 ◽  
Vol 3 (S247) ◽  
pp. 243-250
Author(s):  
I. Ballai ◽  
M. Douglas
Keyword(s):  
Magnetic Field ◽  
Solar Corona ◽  
Solar Disk ◽  
Coronal Loop ◽  
Large Scale ◽  
Theoretical Models ◽  
Coronal Loops ◽  
Quiet Sun ◽  
Propagating Waves ◽  
Global Magnetic Field

AbstractObservations in EUV lines of the solar corona revealed large scale propagating waves generated by eruptive events able to travel across the solar disk for large distances. In the low corona, CMEs are known to generate, e.g. EIT waves which can be used to sample the coronal local and global magnetic field. This contribution presents theoretical models for finding values of magnetic field in the quiet Sun and coronal loops based on the interaction of global waves and local coronal loops as well as results on the generation and propagation of EIT waves. The physical connection between local and global solar coronal events (e.g. flares, EIT waves and coronal loop oscillations) will also be explored.

Excitation and damping of disturbances in cylindrical coronal loops

2005 ◽  
Vol 364 (1839) ◽  
pp. 547-550 ◽  
Author(s):  
Jaume Terradas ◽  
Ramón Oliver ◽  
José Luis Ballester
Keyword(s):  
Boundary Layer ◽  
Coronal Loop ◽  
Normal Mode Analysis ◽  
Resonant Absorption ◽  
Time Dependent ◽  
Mode Analysis ◽  
Coronal Loops ◽  
Two Dimensional ◽  
Magnetohydrodynamic Equations ◽  
Kink Mode

The excitation and damping of transversal coronal loop oscillations is studied using one-and two-dimensional models of line-tied cylindrical loops. By solving the time-dependent magnetohydrodynamic equations it is shown how an initial disturbance generated in the solar corona induces kink mode oscillations. We investigate the effect of the disturbance on a loop with a non-uniform boundary layer. In particular, a strong damping of transversal oscillations due to resonant absorption is found, such as predicted by previous works based on normal mode analysis.

scholarly journals Hybrid Amplifier Modules for Nuclear Measurements in Space Flight Experiments

1980 ◽  
Vol 7 (1-3) ◽  
pp. 35-38
Author(s):  
Walter Funk ◽  
Wolfgang Winkelnkemper
Keyword(s):  
Cost Effectiveness ◽  
Space Flight ◽  
Heavy Ions ◽  
Operating Temperature ◽  
Charged Particles ◽  
Max Planck ◽  
Irradiation Treatment ◽  
Environmental Requirements ◽  
Wide Operating ◽  
Operating Temperature Range

Nuclear electronic instruments for the measurement of the precise energy and time-of-flight of charged particles, e.g. heavy ions, are quite often present on scientific satellites. In addition to the non-trivial electrical requirements, size, weight, and power consumption have to be kept within strict limits for space flight electronics. Furthermore, such instruments must possess a wide operating temperature range and resistance to irradiation. In the interest of cost effectiveness it is desirable to develop modules with a sufficiently wide application to enable their use on more than one mission. Because of the small quantities (expected need is in the order of some hundred circuits per year) and the resistance and capacitance values required, a hybrid thick film approach is considered to be the most economical solution. The development of two amplifier modules took place in a co-operation between the Max-Planck-Institut für Aeronomie in Lindau/Harz (scientific and environmental requirements), the Hahn-Meitner-Institut Berlin (irradiation treatment), the Lehrstuhl für Elektronische Schaltungen of the Ruhr-Universität Bochum (electrical design), and the Philips Forschungslaboratorium Hamburg (technological implementation and production of prototypes). The results and experiences are reported in this paper.

scholarly journals Calculation the Effect of Atomic Number for Projectile and Target on the Electronic Stopping Power

2019 ◽  
Vol 27 (2) ◽  
pp. 170-177
Author(s):  
Roaa Salam Kadhum Al- Hasnawei
Keyword(s):  
Theoretical Result ◽  
Atomic Number ◽  
Heavy Ions ◽  
Theoretical Study ◽  
Charged Particles ◽  
Alpha Particles ◽  
Stopping Power ◽  
Heavy Charged Particles ◽  
Electronic Stopping Power

         In this research, a theoretical study was made to calculate electronic stopping power for heavy charged particles (Protons, Alpha particles, Heavy ions (C,O)) which interact with atomic targets (H,C,O,Si) by using the equation which resulting from distant and close collisions ,as it has been calculating the effect of  atomic number (Z1) for projectiles and the effect of  atomic number (Z2) for targets on the electronic stopping power in range velocities (v=vo,2vo,5vo,10vo).              Mathematical approximative methods are used in the calculation and some of the equation programmed by Matlab language to obtain the theoretical result which is shown in the graphic.

scholarly journals A Thermal Catastrophe in a Resonantly Heated Coronal Loop

1983 ◽  
Vol 102 ◽  
pp. 397-400
Author(s):  
P.C.H. Martens ◽  
M. Kuperus
Keyword(s):  
Magnetic Field ◽  
Thermal Stability ◽  
Coronal Loop ◽  
Coronal Loops ◽  
Natural Explanation ◽  
X Ray ◽  
Magnetic Field Topology ◽  
Coronal Rain ◽  
The Magnetic Field ◽  
Thermal Stability Of

A theory for the thermal stability of hot coronal loops is presented, which is based on the resonant electrodynamic heating theory of Ionson (1982) and the evaporation/condensation scenario of Krall and Antiochos (1980). The theory predicts that gradual changes in the length of a loop or in its magnetic field strength can trigger catastrophic changes in the X-ray visibility of the loop, without the need for a change in the magnetic field topology.A natural explanation is thereby given for the observations of X-ray brightenings in loops and loop evacuations with coronal rain.

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