Chromospheric polarimetry through multi-line observations of the 850 nm spectral region III: Chromospheric jets driven by twisted magnetic fields
C. Quintero Noda, H. Iijima, Y. Katsukawa, T. Shimizu, M. Carlsson, J. de la Cruz Rodríguez, B. Ruiz Cobo, D. Orozco Suárez, T. Oba, T. Anan, M. Kubo, Y. Kawaba… 展开作者
C. Quintero Noda, H. Iijima, Y. Katsukawa, T. Shimizu, M. Carlsson, J. de la Cruz Rodríguez, B. Ruiz Cobo, D. Orozco Suárez, T. Oba, T. Anan, M. Kubo, Y. Kawabata, K. Ichimoto, Y. Suematsu
We investigate the diagnostic potential of the spectral lines at 850 nm for understanding the magnetism of the lower atmosphere. For that purpose, we use a newly developed 3D simulation of a chromospheric jet to check the sensitivity of the spectral lines to this phenomenon as well as our ability to infer the atmospheric information through spectropolarimetric inversions of noisy synthetic data. We start comparing the benefits of inverting the entire spectrum at 850 nm versus only the Ca II 8542 A spectral line. We found a better match of the input atmosphere for the former case, mainly at lower heights. However, the results at higher layers were not accurate. After several tests, we determined that we need to weight more the chromospheric lines than the photospheric ones in the computation of the goodness of the fit. The new inversion configuration allows us to obtain better fits and consequently more accurate physical parameters. Therefore, to extract the most from multi-line inversions, a proper set of weights needs to be estimated. Besides that, we conclude again that the lines at 850 nm, or a similar arrangement with Ca II 8542 A plus Zeeman sensitive photospheric lines, poses the best observing configuration for examining the thermal and magnetic properties of the lower solar atmosphere.
Future solar missions and ground-based telescopes aim to understand the magnetism of the solar chromosphere. We performed a supporting study in Quintero Noda et al. (2016) focused on the infrared Ca II 8542 A line and we concluded that is one of the best candidates because it is sensitive to a large range of atmospheric heights, from the photosphere to the middle chromosphere. However, we believe that it is worth to try improving the results produced by this line observing additional spectral lines. In that regard, we examined the neighbour solar spectrum looking for spectral lines that could …
In this publication we continue the work started in Quintero Noda et al. (2017) examining this time a numerical simulation of a magnetic flux tube concentration. Our goal is to study if the physical phenomena that take place in it, in particular, the magnetic pumping, leaves a specific imprint on the examined spectral lines. We find that the profiles from the interior of the flux tube are periodically dopplershifted following an oscillation pattern that is also reflected in the amplitude of the circular polarization signals. In addition, we analyse the properties of the Stokes profiles at the …
This paper presents a three-dimensional simulation of chromospheric jets with twisted magnetic field lines. Detailed treatments of the photospheric radiative transfer and the equation of states allow us to model realistic thermal convection near the solar surface, which excites various MHD waves and produces chromospheric jets in the simulation. A tall chromospheric jet with a maximum height of 10--11 Mm and lifetime of 8--10 min is formed above a strong magnetic field concentration. The magnetic field lines are strongly entangled in the chromosphere, which helps the chromospheric jet to be dr…
Context. Magnetic reconnection during flares takes place in the corona but a substantial part of flare energy is deposited in the chromosphere. However, high-resolution spectro-polarimetric chromospheric observations of flares are very rare. The most used observables are Ca II 8542 Å and He I 10830 Å. Aims. We aim to study the chromosphere during a C3.6 class flare via spectro-polarimetric observations of the He I D3 line. Methods. We present the first SST/CRISP spectro-polarimetric observations of He I D3. We analyze the data using the inversion code HAZEL, and estimate the LOS velocity and t…
Understanding the initial conditions of star formation requires both observational studies and theoretical works taking into account the magnetic field, which plays an important role in star formation processes. Herein, we study the young nearby dense cloud core L1521 F ($n$(H$_2$) $\sim 10^{4-6}$ cm$^{-3}$) in the Taurus Molecular Cloud. This dense core hosts a 0.2 $M_\odot$ protostar, categorized as a Very Low Luminosity Objects with complex velocity structures, particularly in the vicinity of the protostar. To trace the magnetic field within the dense core, we conducted high sensitivity sub…
Cause of chromospheric opposite polarity intrusions discovered in Sunrise III/SCIP data: MURaM-ChE simulations point to twisted flux ropes
Max-Planck-Institut für Sonnensystemforschung（马克斯·普朗克太阳系统研究所）；National Astronomical Observatory of Japan（日本国立天文台）；Instituto de Astrofísica de Andalucía, CSIC（安达卢西亚天体物理研究所，西班牙高等科学研究委员会）
The analysis of high spectral resolution spectroscopic and spectropolarimetric observations constitute a very powerful way of inferring the dynamical, thermodynamical, and magnetic properties of distant objects. However, these techniques are photon-starving, making it difficult to use them for all purposes. One of the problems commonly found is just detecting the presence of a signal that is buried on the noise at the wavelength of some interesting spectral feature. This is specially relevant for spectropolarimetric observations because typically, only a small fraction of the received light is…
Chromospheric heating and magnetic topology above the shared penumbra of a delta-spot: Multi-line inversions and multi-height magnetic-field extrapolations
Institute for Solar Physics, Dept. of Astronomy, Stockholm University（斯德哥尔摩大学天文系太阳物理研究所）
This paper identifies spectral lines from X-ray to infrared wavelengths which are optimally suited to measuring vector magnetic fields as high as possible in the solar atmosphere. Instrumental and Earth's atmospheric properties, as well as solar abundances, atmospheric properties and elementary atomic physics are considered without bias towards particular wavelengths or diagnostic techniques. While narrowly-focused investigations of individual lines have been reported in detail, no assessment of the comparative merits of all lines has ever been published. Although in the UV, on balance the Mg+…
We present simultaneous photospheric and chromospheric observations of the trailing sunspot in NOAA 10904 during a weak flare eruption (GOES magnitude B7.8), obtained with the Swedish Solar Telescope (SST) in La Palma, Canary Islands. High-resolution \ion{Ca}{ii} $H$ images show a typical two-ribbon structure that has been hitherto only known for larger flares, and the flare appears in a confined region that is discernible by a bright border. The underlying photosphere shows a disturbed penumbral structure with intersecting branches of penumbral filaments. High-resolution Doppler- and vector-m…
We analyzed the full Stokes spectra using simultaneous measurements of the photospheric (FeI 630.15 and 630.25 nm) and chromospheric (MgI b2 517.27 nm) lines. The data were obtained with the HAO/NSO Advanced Stokes Polarimeter, about a near disc center sunspot region, NOAA AR 9661. We compare the characteristics of Stokes profiles in terms of Doppler shifts and asymmetries among the three spectral lines, which helps us to better understand the chromospheric lines and the magnetic and flow fields in different magnetic regions. The main results are: (1) For penumbral area observed by the photosp…
The 3D structure of an active region (AR) filament is studied using nonlinear force-free field (NLFFF) extrapolations based on simultaneous observations at a photospheric and a chromospheric height. To that end, we used the Si I 10827 Å line and the He I 10830 Å triplet obtained with the Tenerife Infrared Polarimeter (TIP) at the VTT (Tenerife). The two extrapolations have been carried out independently from each other and their respective spatial domains overlap in a considerable height range. This opens up new possibilities for diagnostics in addition to the usual ones obtained through a sin…
Using data obtained by the high resolution CRisp Imaging SpectroPolarimeter instrument on the Swedish 1-m Solar Telescope, we investigate the dynamics and stability of quiet-Sun chromospheric jets observed at disk center. Small-scale features, such as Rapid Redshifted and Blueshifted Excursions, appearing as high speed jets in the wings of the H$α$ line, are characterized by short lifetimes and rapid fading without any descending behavior. To study the theoretical aspects of their stability without considering their formation mechanism, we model chromospheric jets as twisted magnetic flux tube…
Deriving the strength and direction of the three-dimensional (3D) magnetic field in the solar atmosphere is fundamental for understanding its dynamics. Volume information on the magnetic field mostly relies on coupling 3D reconstruction methods with photospheric and/or chromospheric surface vector magnetic fields. Infrared coronal polarimetry could provide additional information to better constrain magnetic field reconstructions. However, combining such data with reconstruction methods is challenging, e.g., because of the optical-thinness of the solar corona and the lack and limitations of ste…
We have studied the evolution of magnetic helicity and chirality in an active region over three consecutive solar rotations. The region when it first appeared was named NOAA10923 and in subsequent rotations it was numbered NOAA 10930, 10935 and 10941. We compare the chirality of these regions at photospheric, chromospheric and coronal heights. The observations used for photospheric and chromospheric heights are taken from Solar Vector Magnetograph (SVM) and H_alpha imaging telescope of Udaipur Solar Observatory (USO), respectively. We discuss the chirality of the sunspots and associated H_alph…
Chromospheric observations of sunspot umbrae offer an exceptional view of magneto-acoustic shock phenomena and the impact they have on the surrounding magnetically-dominated plasma. We employ simultaneous slit-based spectro-polarimetry and spectral imaging observations of the chromospheric He I 10830Å and Ca II 8542Å lines to examine fluctuations in the umbral magnetic field caused by the steepening of magneto-acoustic waves into umbral flashes. Following the application of modern inversion routines, we find evidence to support the scenario that umbral shock events cause expansion of the embed…
Hinode observations have revealed intermittent recurrent plasma ejections/jets in the chromosphere. These are interpreted as a result of non-perfectly anti-parallel magnetic reconnection, i.e. component reconnection, between a twisted magnetic flux tube and the pre-existing coronal/chromospheric magnetic field, though the fundamental physics of component reconnection is unrevealed. In this paper, we experimentally reproduced the magnetic configuration and investigated the dynamics of plasma ejections, heating and wave generation triggered by component reconnection in the chromosphere. We set p…
Twisted magnetic fields should be ubiquitous in flare-producing active regions where the magnetic fields are strongly non-potential. It has been shown that reconnection in helical magnetic coronal loops results in plasma heating and particle acceleration distributed within a large volume, including the lower coronal and chromospheric sections of the loops. This scenario can be an alternative to the standard flare model, where particles are accelerated only in a small volume located in the upper corona. We use a combination of MHD simulations and test-particle methods, which describe the develo…
With the advent of a new generation of solar telescopes and instrumentation, the interpretation of chromospheric observations (in particular, spectro-polarimetry) requires new, suitable diagnostic tools. This paper describes a new code, NICOLE, that has been designed for Stokes non-LTE radiative transfer, both for synthesis and inversion of spectral lines and Zeeman-induced polarization profiles, spanning a wide range of atmospheric heights, from the photosphere to the chromosphere. The code fosters a number of unique features and capabilities and has been built from scratch with a powerful pa…
We investigate the linear polarization produced by interstellar dust aligned by the magnetic field in the solar neighborhood (d< 50 pc). We also look for intrinsic effects from circumstellar processes, specifically in terms of polarization variability and wavelength dependence. We aim to detect and map dust clouds which give rise to statistically significant amounts of polarization of the starlight passing through the cloud, and to determine the interstellar magnetic field direction from the position angle of the observed polarization. High-precision broad-band (BVR) polarization observations …
We calculated the time evolution of the free magnetic energy during the 2014-Mar-29 flare (SOL2014-03-29T17:48), the first X-class flare detected by IRIS. The free energy was calculated from the difference between the nonpotential field, constrained by the geometry of observed loop structures, and the potential field. We use AIA/SDO and IRIS images to delineate the geometry of coronal loops in EUV wavelengths, as well as to trace magnetic field directions in UV wavelengths in the chromosphere and transition region. We find an identical evolution of the free energy for both the coronal and chro…
Observations show various jets in the solar atmosphere with significant rotational motions, which may undergo instabilities leading to heat ambient plasma. We study the Kelvin-Helmholtz (KH) instability of twisted and rotating jets caused by the velocity jumps near the jet surface. We derive a dispersion equation with appropriate boundary condition for total pressure (including centrifugal force of tube rotation), which governs the dynamics of incompressible jets. Then, we obtain analytical instability criteria of Kelvin-Helmholtz instability in various cases, which were verified by numerical …
3D simulations of magnetic flux emergence are carried out in a computational domain spanning the upper layers of the convection zone to the lower corona. We use the Oslo Staggered Code to solve the full MHD equations with non-grey and NLTE radiative transfer and thermal conduction along the magnetic field lines. In this paper we concentrate on the later stages of the simulations and study the evolution of the structure of the rising flux in the upper chromosphere and corona, the interaction between the emerging flux and the weak coronal magnetic field initially present, and the associated dyna…
We present H-band (1.65 $μ$m) and SOFIA HAWC+ 154 $μ$m polarization observations of the low-mass core L483. Our H-band observations reveal a magnetic field that is overwhelmingly in the E-W direction, which is approximately parallel to the bipolar outflow that is observed in scattered IR light and in single-dish $^{12}$CO observations. From our 154 $μ$m data, we infer a $\sim$ 45$^{\circ}$ twist in the magnetic field within the inner 5" (1000 au) of L483. We compare these new observations with published single-dish 350 $μ$m polarimetry and find that the 10,000 au scale H-band data match the sm…
Using multi-wavelength observations of SoHO/MDI, SOT-Hinode/blue-continuum (4504 Å), G-band (4305 Å), Ca II H (3968 Å) and TRACE 171 Å, we present the observational signature of highly twisted magnetic loop in AR 10960 during the period 04:43 UT-04:52 UT at 4 June, 2007. SOT-Hinode/blue-continuum (4504 Å) observations show that penumbral filaments of positive polarity sunspot have counter-clock wise twist, which may be caused by the clock-wise rotation of the spot umbrae. The coronal loop, whose one footpoint is anchored in this sunspot, shows strong right-handed twist in chromospheric SOT-Hin…
Magnetic twist of the active region has been measured over a decade using photospheric vector field data, chromospheric H_alpha data, and coronal loop data. The twist and tilt of the active regions have been measured at the photospheric level with the vector magnetic field measurements. The active region NOAA 10930 is a highly twisted emerging region. The same active region produced several flares and has been extensively observed by Hinode. In this paper, we will show the evolution of twist and tilt in this active region leading up to the two X-class flares. We find that the twist initially i…
Magnetic reconnection is a rapid energy release process that is believed to be responsible for flares on the Sun and stars. Nevertheless, such flare-related reconnection is mostly detected to occur in the corona, while there have been few studies concerning the reconnection in the chromosphere or photosphere. Here we present both spectroscopic and imaging observations of magnetic reconnection in the chromosphere leading to a microflare. During the flare peak time, chromospheric line profiles show significant blueshifted/redshifted components on the two sides of the flaring site, corresponding …
Global magnetic fields of active solar-like stars are nowadays routinely detected with spectropolarimetric measurements and are mapped with Zeeman-Doppler imaging (ZDI). However, due to the cancellation of opposite field polarities, polarimetry captures only a tiny fraction of the magnetic flux and cannot assess the overall stellar surface magnetic field if it is dominated by a small-scale component. Analysis of Zeeman broadening in high-resolution intensity spectra can reveal these hidden complex magnetic fields. Historically, there were very few attempts to obtain such measurements for G dwa…
We study the evolution of a mini-filament eruption in a quiet region at the center of the solar disk and its impact on the ambient atmosphere. We used high-spectral resolution imaging spectroscopy in H$α$ acquired by the echelle spectrograph of the Vacuum Tower Telescope (VTT), Tenerife, Spain, photospheric magnetic field observations from the Helioseismic and Magnetic Imager (HMI), and UV/EUV imaging from the Atmospheric Imaging Assembly (AIA) of the Solar Dynamics Observatory (SDO). The H$α$ line profiles were noise-stripped using Principal Component Analysis (PCA) and then inverted to produ…
Context. Recent observations by the Extreme Ultraviolet Imager (EUI) on board Solar Orbiter have characterized prevalent small-scale transient brightenings in the corona above the quiet Sun termed campfires. Aims. In this study we search for comparable brightenings in a numerical model and then investigate their relation to the magnetic field and the processes that drive these events. Methods. We use the MURaM code to solve the 3D radiation MHD equations in a box that stretches from the upper convection zone to the corona. The model self-consistently produces a supergranular network of the mag…
Kratos-polrad: Novel GPU system for Monte-Carlo simulations with consistent polarization calculations
Institute for Astronomy, School of Physics, Zhejiang University（浙江大学物理学院天体物理研究所）；Center for Cosmology and Computational Astrophysics, Institute for Advanced Study in Physics, Zhejiang University（浙江大学物理高等研究院宇宙学与计算天体物理中心）；The Kavli Institute for Astronomy and Astrophysics, Peking University（北京大学柯利天文与天体物理研究所）；Department of Astronomy, School of Physics, Peking University（北京大学物理学院天文学系）
