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Astrophysics Research Centre

School of Mathematics and Physics

Wavenumber spectra of solar magnetic fields based on mosaic SOT/SP raster scans

  • Submitted by: Kirill Kuzanyan, IZMIRAN, Russian Academy of Sciences, Moscow
  • Authors: K. Otsuji, T. Sakurai, K. Kuzanyan, and N. Yokoi
  • Session: Wednesday afternoon posters.

Since the advent of SOHO/MDI, SOLIS, and SDO/HMI full disk solar magnetic field observations, these data can be used to study large scale solar phenomena. In some cases small-scale events may affect global phenomena, but solar magnetic field observations over full disk (or over a wide-enough field of view) with spatial resolution and accuracy comparable to Hinode/SOT are still missing. Furthermore, it is now getting clear that large-scale properties of solar magnetic fields like magnetic helicity are only correctly measured with highest available resolution. The link between large scale and small scale magnetic structures is an important topic that can be tackled with Hinode/SOT.

Our study aims at the determination of spatial spectra of solar small-scale as well as large-scale magnetic fields, simultaneously. While small-scale fields usually reflect the impact of granular convection and background turbulence, large-scale magnetic fields contribute to the long-term evolution of magnetic activity with the solar cycle. Different physical properties are expected from these two ends of the observable data spectrum. The question of energy cascade for magnetic field over a wide range of scales is important to justify numerical modelling.

Having obtained a series of maps of photospheric vector magnetic fields with highest available resolution from Hinode/SOT, we developed a procedure for matching several SOT/SP raster scans taken with relatively little time gap in order to construct a proxy of a large field of view (FOV) magnetogram. First of all, we match two collateral raster scans, and then we are going to apply the same technique to merge two zonal bands of magnetograms. Given the overlap of the FOV of about 10 arcsec in east-west, we were able to collate them. Other large FOV data (e.g. from SDO/HMI) wereare also used as reference for matching the SOT/SP FOV. We reporst our work in progress and present large-scale spatial properties of observable magnetic fields as well as rich statistics of their small-scale properties. In particular, at the small-scale end of the spectra but still above the spatial resolution limit of Hinode we notice features that indicate a possibility of different mechanisms of energy transfers in turbulent cascades.

public/hinode9/schedule/session-06p/v0070.txt · Last modified: 2015/07/30 01:34 (external edit)

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