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Hardi Peter - One of the best experts on this subject based on the ideXlab platform.

  • solar Coronal loops associated with small scale mixed polarity surface magnetic fields
    Astrophysical Journal Supplement Series, 2017
    Co-Authors: L P Chitta, Hardi Peter, S K Solanki, P Barthol, A Gandorfer, L Gizon, J Hirzberger, T L Riethmuller, M Van Noort, Blanco J Rodriguez
    Abstract:

    How and where are Coronal loops rooted in the solar lower atmosphere? The details of the magnetic environment and its evolution at the footpoints of Coronal loops are crucial to understanding the processes of mass and energy supply to the solar Corona. To address the above question, we use high-resolution line-of-sight magnetic field data from the Imaging Magnetograph eXperiment instrument on the Sunrise balloon-borne observatory and Coronal observations from the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory of an emerging active region. We find that the Coronal loops are often rooted at the locations with minor small-scale but persistent opposite-polarity magnetic elements very close to the larger dominant polarity. These opposite-polarity small-scale elements continually interact with the dominant polarity underlying the Coronal loop through flux cancellation. At these locations we detect small inverse Y-shaped jets in chromospheric Ca ii H images obtained from the Sunrise Filter Imager during the flux cancellation. Our results indicate that magnetic flux cancellation and reconnection at the base of Coronal loops due to mixed polarity fields might be a crucial feature for the supply of mass and energy into the Corona.

  • using Coronal seismology to estimate the magnetic field strength in a realistic Coronal model
    Astronomy and Astrophysics, 2015
    Co-Authors: Feng Chen, Hardi Peter
    Abstract:

    Aims. Coronal seismology is used extensively to estimate properties of the Corona, e.g. the Coronal magnetic field strength is derived from oscillations observed in Coronal loops. We present a three-dimensional Coronal simulation, including a realistic energy balance in which we observe oscillations of a loop in synthesised Coronal emission. We use these results to test the inversions based on Coronal seismology. Methods. From the simulation of the Corona above an active region, we synthesise extreme ultraviolet emission from the model Corona. From this, we derive maps of line intensity and Doppler shift providing synthetic data in the same format as obtained from observations. We fit the (Doppler) oscillation of the loop in the same fashion as done for observations to derive the oscillation period and damping time. Results. The loop oscillation seen in our model is similar to imaging and spectroscopic observations of the Sun. The velocity disturbance of the kink oscillation shows an oscillation period of 52.5 s and a damping time of 125 s, which are both consistent with the ranges of periods and damping times found in observations. Using standard Coronal seismology techniques, we find an average magnetic field strength of Bkink = 79 G for our loop in the simulation, while in the loop the field strength drops from roughly 300 G at the Coronal base to 50 G at the apex. Using the data from our simulation, we can infer what the average magnetic field derived from Coronal seismology actually means. It is close to the magnetic field strength in a constant cross-section flux tube, which would give the same wave travel time through the loop. Conclusions. Our model produced a realistic looking loop-dominated Corona, and provides realistic information on the oscillation properties that can be used to calibrate and better understand the result from Coronal seismology.

  • using Coronal seismology to estimate the magnetic field strength in a realistic Coronal model
    arXiv: Solar and Stellar Astrophysics, 2015
    Co-Authors: Feng Chen, Hardi Peter
    Abstract:

    Coronal seismology is extensively used to estimate properties of the Corona, e.g. the Coronal magnetic field strength are derived from oscillations observed in Coronal loops. We present a three-dimensional Coronal simulation including a realistic energy balance in which we observe oscillations of a loop in synthesised Coronal emission. We use these results to test the inversions based on Coronal seismology. From the simulation of the Corona above an active region we synthesise extreme ultraviolet (EUV) emission from the model Corona. From this we derive maps of line intensity and Doppler shift providing synthetic data in the same format as obtained from observations. We fit the (Doppler) oscillation of the loop in the same fashion as done for observations to derive the oscillation period and damping time. The loop oscillation seen in our model is similar to imaging and spectroscopic observations of the Sun. The velocity disturbance of the kink oscillation shows an oscillation period of 52.5s and a damping time of 125s, both being consistent with the ranges of periods and damping times found in observation. Using standard Coronal seismology techniques, we find an average magnetic field strength of $B_{\rm kink}=79$G for our loop in the simulation, while in the loop the field strength drops from some 300G at the Coronal base to 50G at the apex. Using the data from our simulation we can infer what the average magnetic field derived from Coronal seismology actually means. It is close to the magnetic field strength in a constant cross-section flux tube that would give the same wave travel time through the loop. Our model produced not only a realistic looking loop-dominated Corona, but also provides realistic information on the oscillation properties that can be used to calibrate and better understand the result from Coronal seismology.

  • Coronal energy input and dissipation in a solar active region 3d mhd model
    Astronomy and Astrophysics, 2015
    Co-Authors: Philippea Bourdin, Sven Bingert, Hardi Peter
    Abstract:

    Context. We have conducted a 3D MHD simulation of the solar Corona above an active region (AR) in full scale and high resolution, which shows Coronal loops, and plasma flows within them, similar to observations. Aims. We want to find the connection between the photospheric energy input by field-line braiding with the Coronal energy conversion by Ohmic dissipation of induced currents. Methods. To this end we compare the Coronal energy input and dissipation within our simulation domain above di erent fields of view, e.g. for a small loops system in the AR core. We also choose an ensemble of field lines to compare, e.g., the magnetic energy input to the heating per particle along these field lines. Results. We find an enhanced Ohmic dissipation of currents in the Corona above areas that also have enhanced upwards-directed Poynting flux. These regions coincide with the regions where hot Coronal loops within the AR core are observed. The Coronal density plays a role in estimating the Coronal temperature due to the generated heat input. A minimum flux density of about 200 Gauss is needed in the photosphere to heat a field line to Coronal temperatures of about 1 MK. Conclusions. This suggests that the field-line braiding mechanism provides the Coronal energy input and that the Ohmic dissipation of induced currents dominates the Coronal heating mechanism.

  • Coronal loops above an active region observation versus model
    Publications of the Astronomical Society of Japan, 2014
    Co-Authors: Philippea Bourdin, Sven Bingert, Hardi Peter
    Abstract:

    We conducted a high-resolution numerical simulation of the solar Corona above a stable active region. The aim is to test the field line braiding mechanism for a sufficient Coronal energy input. We also check the applicability of scaling laws for Coronal loop properties like the temperature and density. Our 3D MHD model is driven from below by Hinode observations of the photosphere, in particular a high-cadence time series of line-of-sight magnetograms and horizontal velocities derived from the magnetograms. This driving applies stress to the magnetic field and thereby delivers magnetic energy into the Corona, where currents are induced that heat the Coronal plasma by Ohmic dissipation. We compute synthetic Coronal emission that we directly compare to Coronal observations of the same active region taken by Hinode. In the model, Coronal loops form at the same places as they are found in Coronal observations. Even the shapes of the synthetic loops in 3D space match those found from a stereoscopic reconstruction based on STEREO spacecraft data. Some loops turn out to be slightly over-dense in the model, as expected from observations. This shows that the spatial and temporal distribution of the Ohmic heating produces the structure and dynamics of a Coronal loops system close to what is found in observations.

T Wiegelmann - One of the best experts on this subject based on the ideXlab platform.

  • force free field modeling of twist and braiding induced magnetic energy in an active region Corona
    The Astrophysical Journal, 2013
    Co-Authors: Julia K Thalmann, Sanjiv K Tiwari, T Wiegelmann
    Abstract:

    The theoretical concept that braided magnetic field lines in the solar Corona may dissipate a sufficient amount of energy to account for the brightening observed in the active-region (AR) Corona has only recently been substantiated by high-resolution observations. From the analysis of Coronal images obtained with the High Resolution Coronal Imager, first observational evidence of the braiding of magnetic field lines was reported by Cirtain et al. (hereafter CG13). We present nonlinear force-free reconstructions of the associated Coronal magnetic field based on Solar Dynamics Observatory/Helioseismic and Magnetic Imager vector magnetograms. We deliver estimates of the free magnetic energy associated with a braided Coronal structure. Our model results suggest (~100 times) more free energy at the braiding site than analytically estimated by CG13, strengthening the possibility of the AR Corona being heated by field line braiding. We were able to appropriately assess the Coronal free energy by using vector field measurements and we attribute the lower energy estimate of CG13 to the underestimated (by a factor of 10) azimuthal field strength. We also quantify the increase in the overall twist of a flare-related flux rope that was noted by CG13. From our models we find that the overall twist of the flux rope increased by about half a turn within 12 minutes. Unlike another method to which we compare our results, we evaluate the winding of the flux rope's constituent field lines around each other purely based on their modeled Coronal three-dimensional field line geometry. To our knowledge, this is done for the first time here.

  • force free field modeling of twist and braiding induced magnetic energy in an active region Corona
    arXiv: Solar and Stellar Astrophysics, 2013
    Co-Authors: Julia K Thalmann, Sanjiv K Tiwari, T Wiegelmann
    Abstract:

    The theoretical concept that braided magnetic field lines in the solar Corona may dissipate a sufficient amount of energy to account for the brightening observed in the active-region Corona, has been substantiated by high-resolution observations only recently. From the analysis of Coronal images obtained with the High Resolution Coronal Imager, first observational evidence of the braiding of magnetic field lines was reported by Cirtain et al. 2013 (hereafter CG13). We present nonlinear force-free reconstructions of the associated Coronal magnetic field based on vector SDO/HMI magnetograms. We deliver estimates of the free magnetic energy associated to a braided Coronal structure. Our model results suggest (~100 times) more free energy at the braiding site than analytically estimated by CG13, strengthening the possibility of the active-region Corona being heated by field line braiding. We were able to assess the Coronal free energy appropriately by using vector field measurements and attribute the lower energy estimate of CG13 to the underestimated (by a factor of 10) azimuthal field strength. We also quantify the increase of the overall twist of a flare-related flux rope which had been claimed by CG13. From our models we find that the overall twist of the flux rope increased by about half a turn within twelve minutes. Unlike another method, to which we compare our results to, we evaluate the winding of the flux rope's constituent field lines around each other purely based on their modeled Coronal 3D field line geometry -- to our knowledge for the first time.

  • evolution of the flaring active region noaa 10540 as a sequence of nonlinear force free field extrapolations
    Astronomy and Astrophysics, 2008
    Co-Authors: Julia K Thalmann, T Wiegelmann
    Abstract:

    Context. The solar Corona is structured by magnetic fields. As direct measurements of the Coronal magnetic field are not routinely available, it is extrapolated from photospheric vector magnetograms. When magnetic flux emerges from below the solar surface and expands into the Corona, the Coronal magnetic field is destabilized, leading to explosive phenomena like flares or Coronal mass ejections. Aims. We study the temporal evolution of the flaring active region NOAA 10540 and are in particular interested in the free magnetic energy available to power the flares associated with it. Methods. We extrapolated photospheric vector magnetograms measured with the Solar Flare Telescope, located in Tokyo, into the Corona with the help of a nonlinear force-free field model. This Coronal magnetic field model is based on a well-tested multigrid-like optimization code with which we were able to estimate the energy content of the 3D Coronal field, as well as an upper limit for its free magnetic energy. Furthermore, the evolution of the energy density with height and time was studied. Results. The Coronal magnetic field energy in active region 10540 increases slowly during the three days before an M6.1 flare and drops significantly after it. We estimated the energy that was set free during this event as ∝10 25 J. A sequence of nonlinear force-free extrapolations of the Coronal magnetic field shows a build up of magnetic energy before a flare and release of energy during the flare. The drop in magnetic energy of the active region is sufficient to power an M6.1 flare.

  • nonlinear force free modeling of the solar Coronal magnetic field
    arXiv: Astrophysics, 2008
    Co-Authors: T Wiegelmann
    Abstract:

    The Coronal magnetic field is an important quantity because the magnetic field dominates the structure of the solar Corona. Unfortunately direct measurements of Coronal magnetic fields are usually not available. The photospheric magnetic field is measured routinely with vector magnetographs. These photospheric measurements are extrapolated into the solar Corona. The extrapolated Coronal magnetic field depends on assumptions regarding the Coronal plasma, e.g. force-freeness. Force-free means that all non-magnetic forces like pressure gradients and gravity are neglected. This approach is well justified in the solar Corona due to the low plasma beta. One has to take care, however, about ambiguities, noise and non-magnetic forces in the photosphere, where the magnetic field vector is measured. Here we review different numerical methods for a nonlinear force-free Coronal magnetic field extrapolation: Grad-Rubin codes, upward integration method, MHD-relaxation, optimization and the boundary element approach. We briefly discuss the main features of the different methods and concentrate mainly on recently developed new codes.

Jay M Pasachoff - One of the best experts on this subject based on the ideXlab platform.

  • the 2008 august 1 eclipse solar minimum Corona unraveled
    The Astrophysical Journal, 2009
    Co-Authors: Miloslav Druckmuller, V Rusin, P Aniol, Metod Saniga, Jay M Pasachoff, M Minarovjech
    Abstract:

    We discuss the results stemming from observations of the white-light and [Fe XIV] emission Corona during the total eclipse of the Sun of 2008 August 1, in Mongolia (Altaj region) and in Russia (Akademgorodok, Novosibirsk, Siberia). Corresponding to the current extreme solar minimum, the white-light Corona, visible up to 20 solar radii, was of a transient type with well pronounced helmet streamers situated above a chain of prominences at position angles 48°, 130°, 241°, and 322°. A variety of Coronal holes, filled with a number of thin polar plumes, were seen around the poles. Furthering an original method of image processing, stars up to 12 mag, a Kreutz-group comet (C/2008 O1) and a Coronal mass ejection (CME) were also detected, with the smallest resolvable structures being of, and at some places even less than, 1 arcsec. Differences, presumably motions, in the Corona and prominences are seen even with the 19 minutes time difference between our sites. In addition to the high-resolution Coronal images, which show the continuum Corona (K-Corona) that results from electron scattering of photospheric light, images of the overlapping green-emission-line (530.3 nm, [Fe XIV]) Corona were obtained with the help of two narrow-passband filters (centered on the line itself and for the continuum in the vicinity of 529.1 nm, respectively), each with an FWHM of 0.15 nm. Through solar observations, on whose scheduling and details we consulted, with the Solar and Heliospheric Observatory, Hinode's XRT and SOT, Transition Region and Coronal Explorer, and STEREO, as well as Wilcox Solar Observatory and Solar and Heliospheric Observatory/Michelson Doppler Imager magnetograms, we set our eclipse observations in the context of the current unusually low and prolonged solar minimum.

  • the 2008 august 1 eclipse solar minimum Corona unraveled
    arXiv: Solar and Stellar Astrophysics, 2009
    Co-Authors: Miloslav Druckmuller, V Rusin, P Aniol, Metod Saniga, Jay M Pasachoff, M Minarovjech
    Abstract:

    We discuss results stemming from observations of the white-light and [Fe XIV] emission Corona during the total eclipse of the Sun of 2008 August 1, in Mongolia (Altaj region) and in Russia (Akademgorodok, Novosibirsk, Siberia). Corresponding to the current extreme solar minimum, the white-light Corona, visible up to 20 solar radii, was of a transient type with well-pronounced helmet streamers situated above a chain of prominences at position angles 48, 130, 241 and 322 degrees. A variety of Coronal holes, filled with a number of thin polar plumes, were seen around the poles. Furthering an original method of image processing, stars up to 12 magnitude, a Kreutz-group comet (C/2008 O1), and a Coronal mass ejection (CME) were also detected, with the smallest resolvable structures being of, and at some places even less than, 1 arcsec. Differences, presumably motions, in the Corona and prominences are seen even with the 19-min time difference between our sites. In addition to the high-resolution Coronal images, which show the continuum Corona (K-Corona) that results from electron scattering of photospheric light, images of the overlapping green-emission-line (530.3 nm, [Fe XIV]) Corona were obtained with the help of two narrow-passband filters (centered on the line itself and for the continuum in the vicinity of 529.1 nm, respectively), each with FWHM of 0.15 nm. Through solar observations, on whose scheduling and details we consulted, with the Solar and Heliospheric Observatory, Hinode's XRT and SOT, TRACE, and STEREO, as well as Wilcox Solar Observatory and SOHO/MDI magnetograms, we set our eclipse observations in the context of the current unusually low and prolonged solar minimum.

  • the solar Corona
    1997
    Co-Authors: Leon Golub, Jay M Pasachoff, E N Parker
    Abstract:

    1. Introduction 2. Brief history of Coronal studies 3. The Coronal spectrum 4. The solar cycle 5. Ground-based observations 6. Observations from space: I. The first 4 decades 7. Activity of the inner Corona 8. Observations from space: II. Recent missions 9. The solar wind 10. Solar flares and Coronal mass ejections Notes References Index.

M Minarovjech - One of the best experts on this subject based on the ideXlab platform.

  • comparing eclipse observations of the 2008 august 1 solar Corona with an mhd model prediction
    Astronomy and Astrophysics, 2010
    Co-Authors: V Rusin, Miloslav Druckmuller, P Aniol, M Minarovjech, Metod Saniga, Z Mikic, J A Linker, R Lionello, P Riley, V S Titov
    Abstract:

    Context. The structure of the white-light and emission solar Coronas and their MHD modelling are the context of our work. Aims. A comparison is made between the structure of the solar Corona as observed during the 2008 August 1 total eclipse from Mongolia and that predicted by an MHD model. Methods. The model has an improved energy formulation, including the effect of Coronal heating, conduction of heat parallel to the magnetic field, radiative losses, and acceleration by Alfven waves. Results. The white-light Corona, which was visible up to 20 solar radii, was of an intermediate type with well-pronounced helmet streamers situated above a chain of prominences at position angles of 48, 130, 241, and 322 degrees. Two polar Coronal holes, filled with a plethora of thin polar plumes, were observed. High-quality pictures of the green (530.3 nm, Fe XIV) Corona were obtained with the help of two narrow-passband filters (centered at the line itself and the vicinity of 529.1 nm background), with a FWHM of 0.15 nm. Conclusions. The large-scale shape of both the white-light and green Corona was found to agree well with that predicted by the model. In this paper we describe the morphological properties of the observed Corona, and how it compares with that predicted by the model. A more detailed analysis of the quantitative properties of the Corona will be addressed in a future publication.

  • the 2008 august 1 eclipse solar minimum Corona unraveled
    The Astrophysical Journal, 2009
    Co-Authors: Miloslav Druckmuller, V Rusin, P Aniol, Metod Saniga, Jay M Pasachoff, M Minarovjech
    Abstract:

    We discuss the results stemming from observations of the white-light and [Fe XIV] emission Corona during the total eclipse of the Sun of 2008 August 1, in Mongolia (Altaj region) and in Russia (Akademgorodok, Novosibirsk, Siberia). Corresponding to the current extreme solar minimum, the white-light Corona, visible up to 20 solar radii, was of a transient type with well pronounced helmet streamers situated above a chain of prominences at position angles 48°, 130°, 241°, and 322°. A variety of Coronal holes, filled with a number of thin polar plumes, were seen around the poles. Furthering an original method of image processing, stars up to 12 mag, a Kreutz-group comet (C/2008 O1) and a Coronal mass ejection (CME) were also detected, with the smallest resolvable structures being of, and at some places even less than, 1 arcsec. Differences, presumably motions, in the Corona and prominences are seen even with the 19 minutes time difference between our sites. In addition to the high-resolution Coronal images, which show the continuum Corona (K-Corona) that results from electron scattering of photospheric light, images of the overlapping green-emission-line (530.3 nm, [Fe XIV]) Corona were obtained with the help of two narrow-passband filters (centered on the line itself and for the continuum in the vicinity of 529.1 nm, respectively), each with an FWHM of 0.15 nm. Through solar observations, on whose scheduling and details we consulted, with the Solar and Heliospheric Observatory, Hinode's XRT and SOT, Transition Region and Coronal Explorer, and STEREO, as well as Wilcox Solar Observatory and Solar and Heliospheric Observatory/Michelson Doppler Imager magnetograms, we set our eclipse observations in the context of the current unusually low and prolonged solar minimum.

  • the 2008 august 1 eclipse solar minimum Corona unraveled
    arXiv: Solar and Stellar Astrophysics, 2009
    Co-Authors: Miloslav Druckmuller, V Rusin, P Aniol, Metod Saniga, Jay M Pasachoff, M Minarovjech
    Abstract:

    We discuss results stemming from observations of the white-light and [Fe XIV] emission Corona during the total eclipse of the Sun of 2008 August 1, in Mongolia (Altaj region) and in Russia (Akademgorodok, Novosibirsk, Siberia). Corresponding to the current extreme solar minimum, the white-light Corona, visible up to 20 solar radii, was of a transient type with well-pronounced helmet streamers situated above a chain of prominences at position angles 48, 130, 241 and 322 degrees. A variety of Coronal holes, filled with a number of thin polar plumes, were seen around the poles. Furthering an original method of image processing, stars up to 12 magnitude, a Kreutz-group comet (C/2008 O1), and a Coronal mass ejection (CME) were also detected, with the smallest resolvable structures being of, and at some places even less than, 1 arcsec. Differences, presumably motions, in the Corona and prominences are seen even with the 19-min time difference between our sites. In addition to the high-resolution Coronal images, which show the continuum Corona (K-Corona) that results from electron scattering of photospheric light, images of the overlapping green-emission-line (530.3 nm, [Fe XIV]) Corona were obtained with the help of two narrow-passband filters (centered on the line itself and for the continuum in the vicinity of 529.1 nm, respectively), each with FWHM of 0.15 nm. Through solar observations, on whose scheduling and details we consulted, with the Solar and Heliospheric Observatory, Hinode's XRT and SOT, TRACE, and STEREO, as well as Wilcox Solar Observatory and SOHO/MDI magnetograms, we set our eclipse observations in the context of the current unusually low and prolonged solar minimum.

Philippea Bourdin - One of the best experts on this subject based on the ideXlab platform.

  • Coronal energy input and dissipation in a solar active region 3d mhd model
    Astronomy and Astrophysics, 2015
    Co-Authors: Philippea Bourdin, Sven Bingert, Hardi Peter
    Abstract:

    Context. We have conducted a 3D MHD simulation of the solar Corona above an active region (AR) in full scale and high resolution, which shows Coronal loops, and plasma flows within them, similar to observations. Aims. We want to find the connection between the photospheric energy input by field-line braiding with the Coronal energy conversion by Ohmic dissipation of induced currents. Methods. To this end we compare the Coronal energy input and dissipation within our simulation domain above di erent fields of view, e.g. for a small loops system in the AR core. We also choose an ensemble of field lines to compare, e.g., the magnetic energy input to the heating per particle along these field lines. Results. We find an enhanced Ohmic dissipation of currents in the Corona above areas that also have enhanced upwards-directed Poynting flux. These regions coincide with the regions where hot Coronal loops within the AR core are observed. The Coronal density plays a role in estimating the Coronal temperature due to the generated heat input. A minimum flux density of about 200 Gauss is needed in the photosphere to heat a field line to Coronal temperatures of about 1 MK. Conclusions. This suggests that the field-line braiding mechanism provides the Coronal energy input and that the Ohmic dissipation of induced currents dominates the Coronal heating mechanism.

  • Coronal loops above an active region observation versus model
    Publications of the Astronomical Society of Japan, 2014
    Co-Authors: Philippea Bourdin, Sven Bingert, Hardi Peter
    Abstract:

    We conducted a high-resolution numerical simulation of the solar Corona above a stable active region. The aim is to test the field line braiding mechanism for a sufficient Coronal energy input. We also check the applicability of scaling laws for Coronal loop properties like the temperature and density. Our 3D MHD model is driven from below by Hinode observations of the photosphere, in particular a high-cadence time series of line-of-sight magnetograms and horizontal velocities derived from the magnetograms. This driving applies stress to the magnetic field and thereby delivers magnetic energy into the Corona, where currents are induced that heat the Coronal plasma by Ohmic dissipation. We compute synthetic Coronal emission that we directly compare to Coronal observations of the same active region taken by Hinode. In the model, Coronal loops form at the same places as they are found in Coronal observations. Even the shapes of the synthetic loops in 3D space match those found from a stereoscopic reconstruction based on STEREO spacecraft data. Some loops turn out to be slightly over-dense in the model, as expected from observations. This shows that the spatial and temporal distribution of the Ohmic heating produces the structure and dynamics of a Coronal loops system close to what is found in observations.

  • observationally driven 3d magnetohydrodynamics model of the solar Corona above an active region
    Astronomy and Astrophysics, 2013
    Co-Authors: Philippea Bourdin, Sven Bingert, H Peter
    Abstract:

    Aims. The goal is to employ a 3D magnetohydrodynamics (MHD) model including spectral synthesis to model the Corona in an observed solar active region. This will allow us to judge the merits of the Coronal heating mechanism built into the 3D model. Methods. Photospheric observations of the magnetic field and horizontal velocities in an active region are used to drive our Coronal simulation from the bottom. The currents induced by this heat the Corona through Ohmic dissipation. Heat conduction redistributes the energy that is lost in the end through optically thin radiation. Based on the MHD model, we synthesized profiles of Coronal emission lines which can be directly compared to actual Coronal observations of the very same active region. Results. In the synthesized model data we find hot Coronal loops which host siphon flows or which expand and lose mass through draining. These synthesized loops are at the same location as and show similar dynamics in terms of Doppler shifts to the observed structures. This match is shown through a comparison with Hinode data as well as with 3D stereoscopic reconstructions of data from STEREO. Conclusions. The considerable match to the actual observations shows that the field-line braiding mechanism leading to the energy input in our Corona provides the proper distribution of heat input in space and time. From this we conclude that in an active region the field-line braiding is the dominant heating process, at least at the spatial scales available to current observations.