1. Helicity on the Sun: What is it good for anyway? Slide 1 of 10830

2. Slide 2 of 10830 Helicity has done extremely well from 1999- present (much better than my 401K!)

3. Kusano et al (2002) had studied helicity and energy flow into photosphere in AR8100, Nov. 2-5, 1997 -Helicity injection due to vertical flows, 6 x 10 26 Wb 2, comparable with helicity injection due to horizontal flows -Energy injected into corona due to helicity injection, 2 x 10 25 J – larger than emitted by all flares during same period

4. Absolute value of the magnetic helicity induced by photospheric horizontal motions accumulated during the flaring time interval vs. the corresponding GOES X-ray flux integrated over the flaring time. Moon et al, 2008, NOAA 8100 - Impulsive helicity injections episodes coinciding with C, M-class flares. -Both positive and negative helicity in injected by shear motions. - The flare X-ray flux integrated over the X-ray emission time strongly correlates with the magnetic helicity injected during the flaring interval. Park et al 2008; 7 active regions - All major flares were preceded by a significant helicity accumulation, (1.8-16) x 10 42 Mx 2 over 0.5 to a few days. - average helicity change rate in the first phase shows strong correlation with the time- integrated soft X-ray flux Park et al 2010; 378 ARs - (91 large ARs), difference in the magnetic helicity injection rate between flaring ARs and nonflaring ARs by a factor of 2 - GOES C-flare-productive probability as a function of helicity injection displays a sharp boundary between flare-productive ARs and flare-quiet ones.

5. Komm & Hill, 2009, 1009 ARs

7. Reiner, et al. 2010 -NHGV (Normalized Helicity Gradient Variance) is effective at separating flaring and non-flaring active regions and even separates among C-, M-, and X-class flare producing regions. -It also provides advance notice of flare occurrence, as it increases 2–3 days before the flare occurs.

8. You might not need helicity for a flare, but it helps.