0000000000242614

AUTHOR

M. Knoelker

showing 4 related works from this author

FULLY RESOLVED QUIET-SUN MAGNETIC FLUX TUBE OBSERVED WITH THE SUNRISE/IMAX INSTRUMENT

2010

Until today, the small size of magnetic elements in quiet Sun areas has required the application of indirect methods, such as the line-ratio technique or multi-component inversions, to infer their physical properties. A consistent match to the observed Stokes profiles could only be obtained by introducing a magnetic filling factor that specifies the fraction of the observed pixel filled with magnetic field. Here, we investigate the properties of a small magnetic patch in the quiet Sun observed with the IMaX magnetograph on board the balloon-borne telescope Sunrise with unprecedented spatial resolution and low instrumental stray light. We apply an inversion technique based on the numerical s…

PhysicsPhotosphereFlux tubeStray lightFOS: Physical sciencesAstronomy and AstrophysicsField strengthAstrophysicsMagnetic fluxMagnetic fieldAstrophysics - Solar and Stellar AstrophysicsSpace and Planetary ScienceRadiative transferAstrophysics::Solar and Stellar AstrophysicsSunriseSolar and Stellar Astrophysics (astro-ph.SR)The Astrophysical Journal
researchProduct

Transverse component of the magnetic field in the solar photosphere observed by Sunrise

2010

We present the first observations of the transverse component of photospheric magnetic field acquired by the imaging magnetograph Sunrise/IMaX. Using an automated detection method, we obtain statistical properties of 4536 features with significant linear polarization signal. Their rate of occurrence is 1-2 orders of magnitude larger than values reported by previous studies. We show that these features have no characteristic size or lifetime. They appear preferentially at granule boundaries with most of them being caught in downflow lanes at some point in their evolution. Only a small percentage are entirely and constantly embedded in upflows (16%) or downflows (8%).

PhysicsTransverse planeAstrophysics - Solar and Stellar AstrophysicsSpace and Planetary ScienceLinear polarizationGranule (solar physics)SunriseFOS: Physical sciencesAstronomy and AstrophysicsSolar photosphereAstrophysicsSolar and Stellar Astrophysics (astro-ph.SR)Magnetic field
researchProduct

Slender Ca II H fibrils mapping magnetic fields in the low solar chromosphere

2017

S. Jafarzadeh et. al.

010504 meteorology & atmospheric sciencesExtrapolationFOS: Physical scienceschromosphere [Sun]Field strengthAstrophysicsDense forest01 natural sciencesMethods: observational0103 physical sciencesSunriseAstrophysics::Solar and Stellar Astrophysicsobservational [Methods]010303 astronomy & astrophysicsChromosphereSun: magnetic fieldsSolar and Stellar Astrophysics (astro-ph.SR)0105 earth and related environmental sciencesPhysicsSolar observatorySun: chromosphereAstronomy and AstrophysicsMagnetic fieldmagnetic fields [Sun]Astrophysics - Solar and Stellar AstrophysicsSpace and Planetary SciencePhysics::Space PhysicsMagnetohydrodynamics
researchProduct

SUNRISE/IMaX observations of convectively driven vortex flows in the Sun

2010

We characterize the observational properties of the convectively driven vortex flows recently discovered on the quiet Sun, using magnetograms, Dopplergrams and images obtained with the 1-m balloon-borne Sunrise telescope. By visual inspection of time series, we find some 3.1e-3 vortices/(Mm^2 min), which is a factor of 1.7 larger than previous estimates. The mean duration of the individual events turns out to be 7.9 min, with a standard deviation of 3.2 min. In addition, we find several events appearing at the same locations along the duration of the time series (31.6 min). Such recurrent vortices show up in the proper motion flow field map averaged over the time series. The typical vertica…

Rotation periodPhysicsProper motionFOS: Physical sciencesAstronomy and AstrophysicsAstrophysicsVorticityRotationVortexPhysics::Fluid DynamicsAstrophysics - Solar and Stellar AstrophysicsSpace and Planetary ScienceSunriseDifferential rotationAstrophysics::Solar and Stellar AstrophysicsClockwiseSolar and Stellar Astrophysics (astro-ph.SR)
researchProduct