scholarly journals Rapid Disappearance of Penumbra-Like Features near a Flaring Polarity Inversion Line: The Hinode Observations

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
B. Ravindra ◽  
Sanjay Gosain
Keyword(s):  
Magnetic Field ◽  
Vertical Component ◽  
Vector Magnetic Field ◽  
Polarity Inversion ◽  
X Ray ◽  
Horizontal Flows ◽  
Before And After ◽  
Polarity Inversion Line ◽  
The Magnetic Field ◽  
Class Flare

We present the observations of penumbra-like features (PLFs) near a polarity inversion line (PIL) of flaring region. The PIL is located at the moat boundary of active region (NOAA 10960). The PLFs appear similar to sunspot penumbrae in morphology but occupy small area, about6×107 km2, and are not associated with sunspot or pore. We observed a rapid disappearance of the PLFs after a C1.7 class flare, which occurred close to the PIL. The local correlation tracking (LCT) of these features shows presence of horizontal flows directed away from the end-points of the PLFs, similar to the radial outward flow found around regular sunspots, which is also known as the moat flow. Hard X-ray emission, coincident with the location of the PLFs, is found in RHESSI observations, suggesting a spatial correlation between the occurrence of the flare and decay of the PLFs. Vector magnetic field derived from the observations obtained by Hinode spectropolarimeter SOT/SP instrument, before and after the flare, shows a significant change in the horizontal as well as the vertical component of the field, after the flare. The weakening of both the components of the magnetic field in the flare interval suggests that rapid cancellation and/or submergence of the magnetic field in PLFs occurred during the flare interval.

scholarly journals Flare Energy Release in the Lower Solar Atmosphere near the Magnetic Field Polarity Inversion Line

2017 ◽  
Vol 840 (2) ◽  
pp. 84 ◽  
Author(s):  
I. N. Sharykin ◽  
V. M. Sadykov ◽  
A. G. Kosovichev ◽  
S. Vargas-Dominguez ◽  
I. V. Zimovets
Keyword(s):  
Magnetic Field ◽  
Energy Release ◽  
Solar Atmosphere ◽  
Field Polarity ◽  
Polarity Inversion ◽  
Flare Energy ◽  
Polarity Inversion Line ◽  
The Magnetic Field ◽  
Lower Solar Atmosphere

scholarly journals New data-driven method of simulating coronal mass ejections

2019 ◽  
Vol 626 ◽  
pp. A91 ◽  
Author(s):  
Cheng’ao Liu ◽  
Tao Chen ◽  
Xinhua Zhao
Keyword(s):  
Magnetic Field ◽  
Coronal Mass Ejections ◽  
Three Dimensional ◽  
Flux Rope ◽  
Mhd Equations ◽  
Data Driven ◽  
Flux Emergence ◽  
Polarity Inversion ◽  
Polarity Inversion Line ◽  
The Magnetic Field

Context. Coronal mass ejections (CMEs) are large eruptions of plasma and magnetic field from the Sun’s corona. Understanding the evolution of the CME is important to evaluate its impact on space weather. Using numerical simulation, we are able to reproduce the occurrence and evolution process of the CME. Aims. The aim of this paper is to provide a new data-driven method to mimic the coronal mass ejections. By using this method, we can investigate the phsical mechanisms of the flux rope formation and the cause of the CME eruption near the real background. Methods. Starting from a potential magnetic field extrapolation, we have solved a full set of magnetohydrodynamic (MHD) equations by using the conservation element and solution element (CESE) numerical method. The bottom boundary is driven by the vector magnetograms obtained from SDO/HMI and vector velocity maps derived from DAVE4VM method. Results. We present a three-dimensional numerical MHD data-driven model for the simulation of the CME that occurred on 2015 June 22 in the active region NOAA 12371. The numerical results show two elbow-shaped loops formed above the polarity inversion line (PIL), which is similar to the tether-cutting picture previously proposed. The temporal evolutions of magnetic flux show that the sunspots underwent cancellation and flux emergence. The signature of velocity field derived from the tracked magnetograms indicates the persistent shear and converging motions along the PIL. The simulation shows that two elbow-shaped loops were reconnected and formed an inverse S-shaped sigmoid, suggesting the occurrence of the tether-cutting reconnection, which was supported by observations of the Atmospheric Imaging Assembly (AIA) telescope. Analysis of the decline rate of the magnetic field indicates that the flux rope reached a region where the torus instability was triggered. Conclusions. We conclude that the eruption of this CME was caused by multiple factors, such as photosphere motions, reconnection, and torus instability. Moreover, our simulation successfully reproduced the three-component structures of typical CMEs.

scholarly journals Magnetic field configuration in a flaring active region

2014 ◽  
Vol 10 (S305) ◽  
pp. 97-101 ◽  
Author(s):  
J. Palacios ◽  
L. A. Balmaceda ◽  
L. E. Vieira
Keyword(s):  
Magnetic Field ◽  
Continuous Monitoring ◽  
Field Configuration ◽  
Solar Dynamics Observatory ◽  
Vector Magnetic Field ◽  
Solar Dynamics ◽  
The Magnetic Field ◽  
Class Flare ◽  
High Cadence ◽  
Full Disk

AbstractThe Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO) provides continuous monitoring of the Sun's vector magnetic field through full-disk photospheric data with both high cadence and high spatial resolution. Here we investigate the evolution of AR 11249 from March 6 to March 7, 2012. We make use of HMI Stokes imaging, SDO/SHARPs, the HMI magnetic field line-of-sight (LOS) maps and the transverse components of the magnetic field as well as LOS velocity maps in order to detect regions with significant flux emergence and/or cancellation. In addition, we apply the Local Correlation Tracking (LCT) technique to the total and signed magnetic flux data and derive maps of horizontal velocity. From this analysis, we were able to pinpoint localized shear regions (and a shear channel) where penumbrae and pore formation areas, with strong linear polarization signals, are stretched and squeezed, showing also important downflows and upflows. We have also utilized Hinode/SP data and compared them to the HMI-SHARPs and the HMI-Stokes spectrograms. The aforementioned shear channel seems to correspond well with the X-class flare main channel of March 7 2012, as observed in AIA/SDO 171, 304 and 1600 Å.

scholarly journals Enhanced X-ray emission arising from laser-plasma confinement by a strong transverse magnetic field

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Evgeny D. Filippov ◽  
Sergey S. Makarov ◽  
Konstantin F. Burdonov ◽  
Weipeng Yao ◽  
Guilhem Revet ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Transverse Magnetic ◽  
Radiative Properties ◽  
Magnetic Field Direction ◽  
Solid Target ◽  
Total Plasma ◽  
Plasma Confinement ◽  
X Ray ◽  
Magnetic Compression ◽  
The Magnetic Field

AbstractWe analyze, using experiments and 3D MHD numerical simulations, the dynamic and radiative properties of a plasma ablated by a laser (1 ns, 10$$^{12}$$ 12 –10$$^{13}$$ 13 W/cm$$^2$$ 2 ) from a solid target as it expands into a homogeneous, strong magnetic field (up to 30 T) that is transverse to its main expansion axis. We find that as early as 2 ns after the start of the expansion, the plasma becomes constrained by the magnetic field. As the magnetic field strength is increased, more plasma is confined close to the target and is heated by magnetic compression. We also observe that after $$\sim 8$$ ∼ 8  ns, the plasma is being overall shaped in a slab, with the plasma being compressed perpendicularly to the magnetic field, and being extended along the magnetic field direction. This dense slab rapidly expands into vacuum; however, it contains only $$\sim 2\%$$ ∼ 2 % of the total plasma. As a result of the higher density and increased heating of the plasma confined against the laser-irradiated solid target, there is a net enhancement of the total X-ray emissivity induced by the magnetization.

scholarly journals Diurnal variation effect in marine magnetometric surveys: clues from surveys in southeast Brazil

2021 ◽  
Vol 42 (3) ◽  
Author(s):  
Paula Possamai Sergipe ◽  
Yára Regina Marangoni ◽  
Roberto Paulo Zanon dos Santos ◽  
Denise Silva de Moura ◽  
Luigi Jovane
Keyword(s):  
Magnetic Field ◽  
Continental Shelf ◽  
Diurnal Variation ◽  
Brazilian Coast ◽  
Observatory Data ◽  
Before And After ◽  
Corrected Data ◽  
Well Correlation ◽  
The Magnetic Field ◽  
Magnetic Observatories

AbstractThe diurnal variation of the magnetic field cannot be predicted or modeled and for that reason, it is monitored during the magnetic surveys, usually by a stationary magnetometer. However, marine surveys have a practical issue with diurnal monitoring, owing to the distance between the survey, stationary magnetometers, and magnetic observatories. This work aims to verify the use of nearby magnetic observatories to estimate the diurnal variation correction in different marine surveys and evaluate its effectiveness. In this study, we selected surveys at the continental shelf near Santos city (Survey 1), continental slope next to the first survey location (Survey 2), continental shelf near Ubatuba city (Survey 3), and Mamanguá ria in the Paraty city (Survey 4), all southeast to the Brazilian coast. The crossing points were implemented to compare the magnetic field values at different times and days at the same measurement point, before and after the correction. Afterwards, we measure the Pearson’s Correlation of the raw data and the diurnal corrected data in all crossing points of each survey which showed an improvement after correction by the value approximating to 1, which indicates a very well correlation. The Ubatuba and Mamanguá surveys allowed comparing the observatory correction results with the base magnetometer results that were rather similar. Our analyses indicate a satisfactory diurnal correction using the observatory data and the crossing points approach, which can be used for every marine magnetometric survey worldwide placed near the coast (< 280 km) that do not have a stationary magnetometer available.

How the Magnetic Field Impacts the Chiroptical Activities of Helical Copper Enantiomers

2021 ◽  
Author(s):  
jialu wu ◽  
Bo Li ◽  
Hong Wang ◽  
Ying Zhen Lai ◽  
Yue Ye ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solid State ◽  
Thermogravimetric Analysis ◽  
Single Crystal ◽  
Structure Analysis ◽  
Chiral Ligands ◽  
X Ray ◽  
The Magnetic Field

A pair of enantiomers {[Cu(L-pro)(L-tyr)]·2H2O}n (L-1) and {[Cu(D-pro)(D-tyr)]·2H2O}n (D-1) based on the chiral ligands L/D-proline and L/D-tyrosine were synthesized and investigated by single-crystal X-ray structure analysis, IR, thermogravimetric analysis, solid-state...

scholarly journals Properties of the inner penumbral boundary and temporal evolution of a decaying sunspot

2018 ◽  
Vol 620 ◽  
pp. A191 ◽  
Author(s):  
M. Benko ◽  
S. J. González Manrique ◽  
H. Balthasar ◽  
P. Gömöry ◽  
C. Kuckein ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Temporal Evolution ◽  
Vertical Component ◽  
Field Vector ◽  
Linear Increase ◽  
Vertical Magnetic Field ◽  
Magnetic Diffusion ◽  
The Magnetic Field ◽  
Linear Decay

Context. It has been empirically determined that the umbra-penumbra boundaries of stable sunspots are characterized by a constant value of the vertical magnetic field. Aims. We analyzed the evolution of the photospheric magnetic field properties of a decaying sunspot belonging to NOAA 11277 between August 28–September 3, 2011. The observations were acquired with the spectropolarimeter on-board of the Hinode satellite. We aim to prove the validity of the constant vertical magnetic-field boundary between the umbra and penumbra in decaying sunspots. Methods. A spectral-line inversion technique was used to infer the magnetic field vector from the full-Stokes profiles. In total, eight maps were inverted and the variation of the magnetic properties in time were quantified using linear or quadratic fits. Results. We find a linear decay of the umbral vertical magnetic field, magnetic flux, and area. The penumbra showed a linear increase of the vertical magnetic field and a sharp decay of the magnetic flux. In addition, the penumbral area quadratically decayed. The vertical component of the magnetic field is weaker on the umbra-penumbra boundary of the studied decaying sunspot compared to stable sunspots. Its value seem to be steadily decreasing during the decay phase. Moreover, at any time of the sunspot decay shown, the inner penumbra boundary does not match with a constant value of the vertical magnetic field, contrary to what is seen in stable sunspots. Conclusions. During the decaying phase of the studied sunspot, the umbra does not have a sufficiently strong vertical component of the magnetic field and is thus unstable and prone to be disintegrated by convection or magnetic diffusion. No constant value of the vertical magnetic field is found for the inner penumbral boundary.

scholarly journals Recent Ginga Results on Galactic X-Ray Binaries

1992 ◽  
Vol 9 ◽  
pp. 211-215
Author(s):  
Y. Tanaka
Keyword(s):  
Magnetic Field ◽  
Black Hole ◽  
Related Problem ◽  
X Ray ◽  
Field Decay ◽  
X Ray Binaries ◽  
The Magnetic Field ◽  
Black Hole Candidates

AbstractBased on the recent Ginga results, following topics on X-ray binaries are briefly discussed: The cyclotron resonnance features observed from several X-ray pulsars, and related problem of the magnetic field decay. Search for millisec. pulsations from LMXRBs. Very bright transients which are suspected to be new black hole candidates, and an estimation of the number of such black hole sources in our galaxy.

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