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Comparing Solar Activity: 2006-2009 Sunspot Minimum and Historical Grand Minima Analysis

This study explores solar activity during the 2006-2009 sunspot minimum and compares it with historical solar minima: Spoerer, Maunder, and Dalton. Utilizing the paleo-cosmic ray record, the analysis reveals significant insights into cosmic ray intensity variations across different solar cycles. Notably, cosmic ray intensities during 2006-2009 were lower than the Spoerer and Maunder minima but similar to the Gleissberg minimum. The findings suggest that the solar dynamo functioned similarly then and now, highlighting pivotal changes in cosmic radiation and solar behavior over centuries.

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Comparing Solar Activity: 2006-2009 Sunspot Minimum and Historical Grand Minima Analysis

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  1. Using the paleo-cosmic ray record to compare the solar activity during the sunspot minimum of 2006-2009 with those during the Spoerer, Maunder, and Dalton Grand Minima Ken McCracken IPST, University of Maryland. jellore@hinet.net.au NESSC, Boston, 17April, 2014 U. New Hampshire, 14 April, 2014

  2. McCracken and Beer, 2014

  3. THE PALEO- COSMIC RADIATION RECORD GALACTIC COSMIC RADIATION SPALLATION OF ATMOSPHERIC A, N and O. 36Cl 14C 1OBe 5730 y 1.5x106 y TREE RINGS ICE CORE TIME DIFFERENT ATMOSPHERIC AND SEQUESTRATION PROCESSES > 120 investigator years of data

  4. COSMOGENIC NUCLIDE PRODUCTION DURING THE PAST 10,000 YEARS TWO INDEPENDENT MEASUREMENTS OF THE PAST Beer et al, ICRC 2007

  5. M Steinhilber et al, PNAS (USA), 2012

  6. PALEO-COSMIC RAYS - A PROXY FOR SPACE CLIMATE High PCR (“Maunder”) Low PCR (“Modern”) Low sunspot cycles High sunspot cycles Low solar activity High solar activity Low HMF High HMF High radiation environ’t Low radiation environ’t

  7. OTHER SEQUENCES OF GRAND MINIMA- AND >1000 YR LONG INTERVALS BETWEEN M M M D S M S M D D

  8. Dye 3 and North GRIP Annual Data McCracken and Beer, JGR, 2014

  9. THE MAUNDER MINIMUM – UP CLOSE. McCracken and Beer, JGR, 2014

  10. COSMIC RAYS- A COSMIC MAGNETOMETER After Caballero - Lopez et al, 2004

  11. Modulation Potential (Observed) Φ = k. VP . B2(t) / ˂(ΔB)2˃ Helio-magnetic field (inferred) B(t) = B0 . {Φ(t)/ Φ0} 1/α

  12. The HMF (Omni-2) near Earth , 1975-2009 Bmax Bmin Bmax/ Bmin= (1.31-1.63) Average = 1.52

  13. COMPARING THE SOLAR DYNAMO DURING MAUNDER MINIMUM WITH THE PRESENT MODERN MAUNDER Bmax/ Bmin 1.31-1.63 1.30-1.85 Average 1.52 1.54 CONCLUSION- A remarkable similarity- the solar dynamo apparently worked then like now with much weaker magnetic fields.

  14. Comparison of key features of the Minima Name Duration Rise Cycles Peak NM(%) Min.HMF(nT) Spoerer 1440-1540 4 111.3 2.4 Maunder 1645-1715 5 117.0 <2.0 Dalton 1790-1830 2 110.9 2.6 Gleissberg 1880-1910 104.5 3.8 Extended Minimum 2006-9 102.8 3.9 Modern epoch Minima 1954-96 97.7 5.4

  15. COMPARISON OF EXTENDED SUNSPOT MINIMUM 2006-9 AND GRAND MINIMA, 1400-1850 AD. • The cosmic ray intensity during 2006-9 was well below those in the Spoerer and Maunder Minimum, while approaching that in the Gleissberg Minimum. • The cosmic ray intensity increased over 4 to 5 solar cycles at the commencement of the Grand Minima. • The next solar minimum 2019 will determine whether the Sun is going into another Grand Minimum. • The solar dynamo operated during the Maunder Minimum as it does today

  16. THANK YOU

  17. M Steinhilber et al, PNAS (USA), 2012

  18. THE SEQUENCE OF GRAND MINIMA- 950-2000 AD - OUR CALIBRATION ERA. Space Era Level In “Grand Minimum” ~40% of time!

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