scholarly journals Magnetic field and radiative transfer modelling of a quiescent prominence

2014 ◽  
Vol 567 ◽  
pp. A123 ◽  
Author(s):  
S. Gunár ◽  
P. Schwartz ◽  
J. Dudík ◽  
B. Schmieder ◽  
P. Heinzel ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Radiative Transfer ◽  
Quiescent Prominence ◽  
Transfer Modelling

scholarly journals Modelling of quiescent prominence fine structures

2013 ◽  
Vol 8 (S300) ◽  
pp. 59-68 ◽  
Author(s):  
S. Gunár
Keyword(s):  
Magnetic Field ◽  
Fine Structure ◽  
Radiative Transfer ◽  
Structure Formation ◽  
Current Status ◽  
Quiescent Prominence ◽  
Future Directions ◽  
The Future ◽  
Fine Structures ◽  
Transfer Modelling

AbstractWe review here the current status and the latest results of the modelling of quiescent prominence fine structures. We begin with the simulations of the prominence magnetic field configurations, through an overview of the modelling of the fine structure formation and dynamics, and with the emphasis on the radiative transfer modelling of the realistic prominence fine structures. We also illuminate the future directions of the field that lie in the combining of the existing approaches into more complex multi-disciplinary models.

scholarly journals Radiative-transfer modelling of funnel flows

2007 ◽  
Vol 3 (S243) ◽  
pp. 83-94
Author(s):  
Tim J. Harries
Keyword(s):  
Numerical Methods ◽  
Radiative Transfer ◽  
Emission Line ◽  
Main Sequence ◽  
Line Profiles ◽  
Stellar Radius ◽  
Transfer Modelling ◽  
Synthetic Line ◽  
Made In ◽  
Geometry And Kinematics

AbstractEmission line profiles from pre-main-sequence objects accreting via magnetically-controlled funnel flows encode information on the geometry and kinematics of the material on stellar radius scales. In order to extract this information it is necessary to perform radiative-transfer modelling of the gas to produce synthetic line profiles. In this review I discuss the physics that needs to be included in such models, and the numerical methods and assumptions that are used to render the problem tractable. I review the progress made in the field over the last decade, and summarize the main successes and failures of the modelling work.

scholarly journals First clear detection of the CCS Zeeman splitting toward the pre-stellar core, Taurus Molecular Cloud 1

2019 ◽  
Author(s):  
Fumitaka Nakamura ◽  
Seiji Kameno ◽  
Takayoshi Kusune ◽  
Izumi Mizuno ◽  
Kazuhito Dobashi ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Radiative Transfer ◽  
Field Strength ◽  
Magnetic Flux ◽  
Molecular Cloud ◽  
Sound Speed ◽  
Flux Ratio ◽  
Zeeman Splitting ◽  
Line Of Sight ◽  
Taurus Molecular Cloud

Abstract We report the first clear detection of the Zeeman splitting of a CCS emission line at 45 GHz toward the nearby pre-stellar dense filament, Taurus Molecular Cloud 1 (TMC-1). We observed HC$_3$N non-Zeeman lines simultaneously with the CCS line, and did not detect any significant splitting of the HC$_3$N lines. Thus, we conclude that our detection of CCS Zeeman splitting is robust. The derived line-of-sight magnetic field strength is about $117 \pm 21 \, \mu$G, which corresponds to a normalized mass-to-magnetic flux ratio of 2.2 if we adopt an inclination angle of 45$^\circ$. Thus, we conclude that the TMC-1 filament is magnetically supercritical. Recent radiative transfer calculations of the CCS and HC$_3$N lines along the line of sight suggest that the filament is collapsing with a speed of $\sim$0.6 km s$^{-1}$, which is comparable to three times the isothermal sound speed. This infall velocity appears to be consistent with the evolution of a gravitationally infalling core.

scholarly journals A study of the approaches used to retrieve aerosol extinction, as applied to limb observations made by OSIRIS and SCIAMACHY

2018 ◽  
Vol 11 (6) ◽  
pp. 3433-3445 ◽  
Author(s):  
Landon A. Rieger ◽  
Elizaveta P. Malinina ◽  
Alexei V. Rozanov ◽  
John P. Burrows ◽  
Adam E. Bourassa ◽  
...  
Keyword(s):  
Particle Size ◽  
Radiative Transfer ◽  
A Priori ◽  
Stratospheric Aerosol ◽  
Aerosol Extinction ◽  
Transfer Modelling ◽  
Inversion Techniques ◽  
And Inversion ◽  
Good Agreement

Abstract. Limb scatter instruments in the UV–vis spectral range have provided long-term global records of stratospheric aerosol extinction important for climate records and modelling. While comparisons with occultation instruments show generally good agreement, the source and magnitude of the biases arising from retrieval assumptions, approximations in the radiative transfer modelling and inversion techniques have not been thoroughly characterized. This paper explores the biases between SCIAMACHY v1.4, OSIRIS v5.07 and SAGE II v7.00 aerosol extinctions through a series of coincident comparisons as well as simulation and retrieval studies to investigate the cause and magnitude of the various systematic differences. The effect of a priori profiles, particle size assumptions, radiative transfer modelling, inversion techniques and the different satellite datasets are explored. It is found that the assumed a priori profile can have a large effect near the normalization point, as well as systematic influence at lower altitudes. The error due to particle size assumptions is relatively small when averaged over a range of scattering angles, but individual errors depend on the particular scattering angle, particle size and measurement vector definition. Differences due to radiative transfer modelling introduce differences between the retrieved products of less than 10 % on average, but can introduce vertical structure. The combination of the different scenario simulations and the application of both algorithms to both datasets enable the origin of some of the systematic features such as high-altitude differences when compared to SAGE II to be explained.

scholarly journals Polarized radiative transfer, rotation measure fluctuations, and large-scale magnetic fields

2019 ◽  
Vol 490 (2) ◽  
pp. 1697-1713
Author(s):  
Alvina Y L On ◽  
Jennifer Y H Chan ◽  
Kinwah Wu ◽  
Curtis J Saxton ◽  
Lidia van Driel-Gesztelyi
Keyword(s):  
Magnetic Field ◽  
Radiative Transfer ◽  
Magnetic Fields ◽  
Large Scale ◽  
Longitudinal Direction ◽  
Density Fluctuations ◽  
Transport Processes ◽  
Spatial Correlations ◽  
Rotation Measure ◽  
Radiative Transfer Equations

ABSTRACT Faraday rotation measure (RM) at radio wavelengths is commonly used to diagnose large-scale magnetic fields. It is argued that the length-scales on which magnetic fields vary in large-scale diffuse astrophysical media can be inferred from correlations in the observed RM. RM is a variable which can be derived from the polarized radiative transfer equations in restrictive conditions. This paper assesses the usage of rotation measure fluctuation (RMF) analyses for magnetic field diagnostics in the framework of polarized radiative transfer. We use models of various magnetic field configurations and electron density distributions to show how density fluctuations could affect the correlation length of the magnetic fields inferred from the conventional RMF analyses. We caution against interpretations of RMF analyses when a characteristic density is ill defined, e.g. in cases of lognormal-distributed and fractal-like density structures. As the spatial correlations are generally not the same in the line-of-sight longitudinal direction and the sky plane direction, one also needs to clarify the context of RMF when inferring from observational data. In complex situations, a covariant polarized radiative transfer calculation is essential to capture all aspects of radiative and transport processes, which would otherwise ambiguate the interpretations of magnetism in galaxy clusters and larger scale cosmological structures.

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