Tag Archives: magnetic fields

195. Cross-Referenced NOAA Active Region List for Multi-Rotation Active Regions, 2011-2019 Now Available

Contributed by Emily Mason. Posted on September 22, 2023

It is well known that many active regions (ARs) last longer than one solar rotation, however, they are often assigned one NOAA AR number for each rotation. This work lists most, if not all, of the ARs that are a same AR but with different AR numbers.

17. Is the recent discovery of the multi-cell meridional circulation a threat to the flux-transport dynamo?

Contributed by Bidya Binay Karak. Posted on May 27, 2014

Motivated by recent observations we have explored whether the flux-transport dynamo model can work with multi-cell meridional flow. We find that it can work when certain conditions are fulfilled.

11. The long-term trend in magnetic fields of sunspot umbrae

Contributed by Fraser Watson. Posted on April 25, 2014

I investigate the possible long term decrease in umbral magnetic field strengths from 1998-2006. Whereas a decrease of 800 Gauss in umbral magnetic fields has been reported between 1998 and 2012, the HMI and MDI data indicate a decrease of only around 300 Gauss. The continuing availability of the excellent HMI data set will allow us to continue to refine this study as solar cycle 24 evolves.