Magnetic Helicity Injection and Sigmoidal Coronal Loops

We analyzed the magnetic helicity injection in NOAA Active Region 8011 with the method proposed by Kusano et al. (2002). It was found that the helical geometry of a sigmoidal loop in this region is consistent with the magnetic helicity injected from the foot points of the loop. We also made a statistical study of the correlation between X-ray intensity and magnetic helicity injection. We found that the sum of the absolute values of the magnetic helicity injection shows good correlation with the X-ray luminosity. The estimated flux of magnetic free energy injection is not highly correlated with the X-ray flux, because the former quantity is overestimated in our simple method.