Physics major Stella Ocker publishes in Astrophysical Journal

Congratulations to Stella Ocker, junior, for her publication in Astrophysical Journal, co-authored with Gordon Petrie of the National Solar Observatory (NSO).  Ocker's research took place in Boulder, Colorado as part of the NSO Research Experiences for Undergraduates Program sponsored by the National Science Foundation.

Spatial maps of solar active region NOAA 11158

Ocker, Stella Koch and Gordon Petrie. 2016. The effects of spatial smoothing on solar magnetic helicity parameters and the hemispheric helicity sign rule. Astrophysical Journal 832, no. 2: 162.

Partial abstract:
"The hemispheric preference for negative/positive helicity to occur in the northern/southern solar hemisphere provides clues to the causes of twisted, flaring magnetic fields. Previous studies on the hemisphere rule may have been affected by seeing from atmospheric turbulence. Using Hinode/SOT-SP data spanning 2006–2013, we studied the effects of two spatial smoothing tests that imitate atmospheric seeing: noise reduction by ignoring pixel values weaker than the estimated noise threshold, and Gaussian spatial smoothing."