[MOVIE] Quiet-sun magnetic field observed with IMaX
Quiet-Sun magnetic fields observed with IMaX
In order to understand processes that govern solar activity, we must disentangle how the magnetic field interacts with the solar plasma and guides the conversion of energy between its mechanical, magnetic, radiative, and thermal forms.
The photosphere represents the key interaction region: thermal, kinetic, and magnetic energy all are of the same order of magnitude and most easily transform from one form into another. This interaction in turn leads to the creation of a rich variety of magnetic structures, from sunspots down to intense magnetic field concentrations on a length scale of 100 km or less. This structuring provides the need to obtain data with a homogeneous and constant resolution of such length scales. One possibility to fulfill this requirement is to fly a telescope carried by a stratospheric balloon.
The Sunrise balloon-borne solar observatory consists of a 1 m aperture Gregory telescope, a UV filter imager, an imaging vector polarimeter, an image stabilization system, and further infrastructure. The first science flight of Sunrise yielded high-quality data that revealed the structure, dynamics, and evolution of solar convection, oscillations, and magnetic fields at a resolution of around 100 km in the quiet Sun.
The Imaging Magnetograph eXperiment (IMaX) operates in the Fe I 525.02 nm line (a Zeeman triplet with Landé factor g = 3). Images in polarized light covering 50 × 50 arcsec are recorded at a spectral resolution of 85 mÅ, normally at four wavelengths within the spectral line and one in the nearby continuum. The full Stokes vector in these five wavelengths at a noise level of 10−3 is obtained in 30 s, which is the typical cadence for most of the observations. The number of wavelength points (between 3 and 12) and of polarization states can be varied to obtain a higher cadence, or a better rendering of the line profile shape.
The movie shows IMaX data products. Clockwise from upper left: continuum intensity at 525.04 nm, LOS velocity, total net linear polarization averaged over the line and the similarly averaged Stokes V, obtained from Fe I 525.02 nm. All images based on the reconstructed data except for the linear polarisation image.