The Sun's Magnetic Field During The Maunder Minimum And Modern Risks From A Weak Field
Abstract
Recent solar conditions include a prolonged solar minimum (2005-2009) and the recent solar maximum, which does not seem fully recovered in terms of the Heliospheric Magnetic Field (HMF) strength when compared to the previous maximum values. These anomalies may indicate that we are entering an era of lower solar activity than observed at other times during the space age. We study past solar grand minima, especially the Maunder period (1645-1715) and its unusually low sunspot numbers to gain further insight into grand minima. We have used the theory of Schwadron et al. [2010] to find the time scale parameters associated with three processes attributed to the magnetic flux balance in the heliosphere using chi-square analysis. We use paleocosmic data and Omni2 data to find the fundamental timescales that influence heliospheric field evolution through conversion or opening of magnetic flux from coronal mass ejections into the ambient heliospheric field, removal or loss of the ambient heliospheric field through magnetic reconnection, and interchange reconnection between coronal mass ejection magnetic flux and ambient heliospheric magnetic flux. We apply our method to two cases: a case where there is no floor flux (for which the minimum value obtained for the HMF at 1 AU in the predicted historic record is 2.92nT) and a case where there is a flux floor (for which the minimum value obtained for the HMF at 1 AU in the predicted historic record is 3.21 nT and the floor flux obtained for this case is 10.99×1013 Wb). We obtained very close reduced chi-square values for the two cases, indicating that (if any) the floor flux should be limited to values significantly smaller than what was found in previous studies. Our results show how the heliospheric magnetic field may evolve through periods of extremely low activity, which could likely be the situation for the coming years. Using these results as the predicted HMF, we deduce the modulation potential of Galactic Cosmic Rays (GCRs) to obtain dose rates for the coming solar cycle. We use these results to predict the most conservative estimations of the time to 3% risk of exposure-induced death (REID) in interplanetary space.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFMSH51C2601R
- Keywords:
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- 5421 Interactions with particles and fields;
- PLANETARY SCIENCES: SOLID SURFACE PLANETSDE: 7513 Coronal mass ejections;
- SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMYDE: 7514 Energetic particles;
- SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMYDE: 7984 Space radiation environment;
- SPACE WEATHER