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

McCracken and Beer, 2014

GALACTIC COSMIC RADIATION SPALLATION OF ATMOSPHERIC A, N and O. TIME 1O Be ICE CORE THE PALEO- COSMIC RADIATION RECORD TREE RINGS 14 C DIFFERENT ATMOSPHERIC AND SEQUESTRATION PROCESSES 5730 y 1.5x10 6 y 36 Cl > 120 investigator years of data

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

Steinhilber et al, PNAS (USA), 2012 M

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

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

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

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

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

Modulation Potential (Observed) Φ = k. V P. B 2 (t) / ˂ (ΔB) 2 ˃ Helio-magnetic field (inferred) B(t) = B 0. {Φ(t)/ Φ 0 } 1/α

The HMF (Omni-2) near Earth, B max B min B max / B min = ( ) Average = 1.52

COMPARING THE SOLAR DYNAMO DURING MAUNDER MINIMUM WITH THE PRESENT MODERN MAUNDER B max / B min Average CONCLUSION- A remarkable similarity- the solar dynamo apparently worked then like now with much weaker magnetic fields.

Name Duration Rise Cycles Peak NM(%) Min.HMF(nT) Spoerer Maunder <2.0 Dalton Gleissberg Extended Minimum Modern epoch Minima Comparison of key features of the Minima

COMPARISON OF EXTENDED SUNSPOT MINIMUM AND GRAND MINIMA, AD. - The cosmic ray intensity during 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

THANK YOU

Steinhilber et al, PNAS (USA), 2012 M

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