Search Publications
STIX X-ray microflare observations during the Solar Orbiter commissioning phase
Massa, Paolo; Krucker, Säm; Piana, Michele +34 more
Context. The Spectrometer/Telescope for Imaging X-rays (STIX) is the hard X-ray instrument onboard Solar Orbiter designed to observe solar flares over a broad range of flare sizes.
Aims: We report the first STIX observations of solar microflares recorded during the instrument commissioning phase in order to investigate the STIX performance at…
Machine learning initialization to accelerate Stokes profile inversions
Ruiz Cobo, B.; Quintero Noda, C.; Orozco Suárez, D. +3 more
Context. At present, an exponential growth in scientific data from current and upcoming solar observatories is expected. Most of the data consist of high spatial and temporal resolution cubes of Stokes profiles taken in both local thermodynamic equilibrium (LTE) and non-LTE spectral lines. The analysis of such solar observations requires complex i…
Solar prominence diagnostics from non-LTE modelling of Mg II h&k line profiles
Barczynski, K.; Schmieder, B.; Labrosse, N. +1 more
Aims: We investigate a new method to for obtaining the plasma parameters of solar prominences observed in the Mg II h&k spectral lines by comparing line profiles from the IRIS satellite to a bank of profiles computed with a one-dimensional non-local thermodynamic equilibrium (non-LTE) radiative transfer code.
Methods: Using a grid of…
Non-LTE inversions of a confined X2.2 flare. I. The vector magnetic field in the photosphere and chromosphere
Leenaarts, J.; Pomoell, J.; Price, D. J. +7 more
Context. Obtaining an accurate measurement of magnetic field vector in the solar atmosphere is essential for studying changes in field topology during flares and reliably modelling space weather.
Aims: We tackle this problem by applying various inversion methods to a confined X2.2 flare that occurred in NOAA AR 12673 on 6 September 2017 and c…
The active region source of a type III radio storm observed by Parker Solar Probe during encounter 2
Barczynski, K.; Mandrini, C. H.; Bale, S. D. +6 more
Context. We investigated the source of a type III radio burst storm during encounter 2 of NASA's Parker Solar Probe (PSP) mission.
Aims: It was observed that in encounter 2 of NASA's PSP mission there was a large amount of radio activity and, in particular, a noise storm of frequent, small type III bursts from 31 March to 6 April 2019. Our ai…
Combining magneto-hydrostatic constraints with Stokes profiles inversions. II. Application to Hinode/SP observations
Pastor Yabar, A.; Ruiz Cobo, B.; Borrero, J. M.
Context. Inversion techniques applied to the radiative transfer equation for polarized light are capable of inferring the physical parameters in the solar atmosphere (temperature T, magnetic field B, and line-of-sight velocity vlos) from observations of the Stokes vector (i.e., spectropolarimetric observations) in spectral lines. Infere…
Magnetic properties on the boundary of an evolving pore
Jurčák, J.; Bello González, N.; García-Rivas, M.
Context. Analyses of the magnetic properties on umbrae boundaries have led to the Jurčák criterion, which states that umbra-penumbra boundaries in stable sunspots are equally defined by a constant value of the vertical magnetic field, Bvercrit, and by a 50% continuum intensity of the quiet Sun, IQS. Umbrae with ver…
Penumbral decay observed in active region NOAA 12585
Guglielmino, S. L.; Romano, P.; Rouppe van der Voort, L. H. M. +3 more
Context. The physical conditions leading the sunspot penumbra decay are poorly understood so far.
Aims: We investigate the photospheric magnetic and velocity properties of a sunspot penumbra during the decay phase to advance the current knowledge of the conditions leading to this process.
Methods: A penumbral decay was observed with the …
Comparison of active region upflow and core properties using simultaneous spectroscopic observations from IRIS and Hinode
Barczynski, Krzysztof; Brooks, David H.; Kleint, Lucia +2 more
Context. The origin of the slow solar wind is still an open issue. It has been suggested that upflows at the edge of active regions are a possible source of the plasma outflow and therefore contribute to the slow solar wind.
Aims: We investigate the origin and morphology of the upflow regions and compare the upflow region and the active regio…
Multiwavelength observations of a metric type-II event
Hillaris, A.; Patsourakos, S.; Nindos, A. +1 more
We have studied a complex metric radio event that originated in a compact flare, observed with the ARTEMIS-JLS radiospectrograph on February 12, 2010. The event was associated with a surge observed at 195 and 304 Å and with a coronal mass ejection observed by instruments on board STEREO A and B near the eastern and western limbs respectively. On t…