scholarly journals High resolution magnetic field measurements in hydrogen and helium plasmas using active laser spectroscopy

2018 ◽  
Vol 89 (10) ◽  
pp. 10D126 ◽  
Author(s):  
Abdullah Zafar ◽  
Elijah Martin ◽  
Steve Shannon
Keyword(s):  
Magnetic Field ◽  
High Resolution ◽  
Laser Spectroscopy ◽  
Field Measurements ◽  
Active Laser ◽  
Magnetic Field Measurements

scholarly journals High resolution magnetic field measurements in high-mass star-forming regions using masers

2016 ◽  
Author(s):  
Gabriele Surcis ◽  
Wouter H.T. Vlemmings ◽  
Huib Jan van Langevelde ◽  
Busaba Hutawarakorn Kramer
Keyword(s):  
Magnetic Field ◽  
High Resolution ◽  
Field Measurements ◽  
High Mass ◽  
Mass Star ◽  
Star Forming ◽  
Star Forming Regions ◽  
Magnetic Field Measurements

scholarly journals Magnetohydrostatic modeling of AR11768 based on a SUNRISE/IMaX vector magnetogram

2020 ◽  
Vol 640 ◽  
pp. A103 ◽  
Author(s):  
X. Zhu ◽  
T. Wiegelmann ◽  
S K. Solanki
Keyword(s):  
Magnetic Field ◽  
High Resolution ◽  
Field Measurements ◽  
Plasma Pressure ◽  
Photospheric Magnetic Field ◽  
Solar Photosphere ◽  
Free Layer ◽  
Lower Boundary Condition ◽  
Magnetic Field Measurements ◽  
The Magnetic Field

Context. High-resolution magnetic field measurements are routinely only done in the solar photosphere. Higher layers, such as the chromosphere and corona, can be modeled by extrapolating these photospheric magnetic field vectors upward. In the solar corona, plasma forces can be neglected and the Lorentz force vanishes. This is not the case in the upper photosphere and chromosphere where magnetic and nonmagnetic forces are equally important. One way to deal with this problem is to compute the plasma and magnetic field self-consistently, in lowest order with a magnetohydrostatic (MHS) model. The non-force-free layer is rather thin and MHS models require high-resolution photospheric magnetic field measurements as the lower boundary condition. Aims. We aim to derive the magnetic field, plasma pressure, and density of AR11768 by applying the newly developed extrapolation technique to the SUNRISE/IMaX data embedded in SDO/HMI magnetogram. Methods. We used an optimization method for the MHS modeling. The initial conditions consist of a nonlinear force-free field (NLFFF) and a gravity-stratified atmosphere. During the optimization procedure, the magnetic field, plasma pressure, and density are computed self-consistently. Results. In the non-force-free layer, which is spatially resolved by the new code, Lorentz forces are effectively balanced by the gas pressure gradient force and gravity force. The pressure and density are depleted in strong field regions, which is consistent with observations. Denser plasma, however, is also observed at some parts of the active region edges. In the chromosphere, the fibril-like plasma structures trace the magnetic field nicely. Bright points in SUNRISE/SuFI 3000 Å images are often accompanied by the plasma pressure and electric current concentrations. In addition, the average of angle between MHS field lines and the selected chromospheric fibrils is 11.8°, which is smaller than those computed from the NLFFF model (15.7°) and linear MHS model (20.9°). This indicates that the MHS solution provides a better representation of the magnetic field in the chromosphere.

scholarly journals High Resolution Magnetic Field Measurements in the Sunspot Photosphere

1993 ◽  
Vol 141 ◽  
pp. 11-19
Author(s):  
Axel Hofmann ◽  
Wolfgang Schmidt ◽  
Horst Balthasar ◽  
Theodore T. Tarbell ◽  
Zoe A. Frank
Keyword(s):  
Magnetic Field ◽  
High Resolution ◽  
Field Strength ◽  
Spectral Resolution ◽  
Field Measurements ◽  
Brightness Variation ◽  
Longitudinal Component ◽  
Azimuthal Variation ◽  
Magnetic Field Measurements ◽  
The Magnetic Field

AbstractWe analysed calibrated Stokes V magnetograms and simultaneously measured Stokes I spectra of high spatial and spectral resolution taken in a medium sized sunspot. We found a clear (anti-) correlation between the brightness variation of penumbral structures and the longitudinal component (B*cosγ) of the magnetic field. No azimuthal variation of the amount of the magnetic field strength (B) was observed across dark and bright structures. There the field is more vertical in bright filaments compared to dark ones.

High-Resolution Magnetic Field Measurements of RR Lyrae Stars with SemPol

2009 ◽  
Author(s):  
E. Guggenberger ◽  
K. Kolenberg ◽  
S. C. Marsden ◽  
I. A. Waite ◽  
H. F. Henrichs ◽  
...  
Keyword(s):  
Magnetic Field ◽  
High Resolution ◽  
Field Measurements ◽  
Rr Lyrae Stars ◽  
Rr Lyrae ◽  
Magnetic Field Measurements ◽  
Lyrae Stars
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