Helioseismology from SODISM and HMI Intensity Images

TL;DR

This study analyzes helioseismic data from PICARD/SODISM and SDO/HMI to extract mode parameters, comparing the rotation profiles derived from both instruments despite differences in data quality and coverage.

Contribution

It provides a comparative analysis of helioseismology results from two different solar observation instruments, highlighting their compatibility despite varying data quality.

Findings

SODISM data has lower signal-to-noise ratio and duty cycle than HMI.

Fewer modes were successfully fitted from SODISM data.

Rotation profiles from both instruments are compatible within errors.

Abstract

Continuum intensity images from PICARD/SODISM and SDO/HMI covering a 209 days period in 2011 are analyzed in order to extract mode parameters for spherical harmonics up to $l=100$. SODISM helioseismology signal is affected by the low orbit of PICARD and by important gaps and CCD persistence effects. SODISM intensity signal has a lower signal to noise ratio and duty cycle than HMI and less modes were successfully fitted over the same period. A comparison of the rotation profiles obtained from both sets of continuum images shows however that the results remain compatible within one standard deviation of HMI formal errors.