An analysis of heliospheric magnetic field flux based on sunspot number from 1749 to today and prediction for the coming solar minimum

Abstract

[1] It is now well established that many bulk properties of the solar wind rise and fall with the solar cycle, and the heliospheric magnetic field (HMF) intensity is no exception. The HMF intensity is seen to be maximum around the time of solar maximum, lowest during solar minimum, and lower still during the recent protracted solar minimum 2006-2009. One explanation of this behavior can be found in the theory of Schwadron et al. (2010) that argues magnetic flux is injected into interplanetary space by coronal mass ejection eruptions and removed by reconnection in the low solar atmosphere. This produces an HMF intensity that is correlated with sunspot number, and the rapid injection of flux followed by the slow removal by reconnection results in a hysteresis effect that is readily evident in the observations. Here for the first time we apply this theory to the sunspot record going back to 1749 and compare favorably our predictions to the results derived from 10 Be observations. We also make a prediction for the coming solar minimum based on results from the Dalton Minimum.

Does the worsening galactic cosmic radiation environment observed by CRaTER preclude future manned deep space exploration?

“…The trends in weakening solar activity are extremely consistent with the beginning of a period from 1790 to 1830 called the Dalton grand minimum [ Goelzer et al , ] or alternatively the less extreme Gleissberg minimum in the period 1890–1920 [ Smith et al , ]. Specifically, in the case of the Dalton minimum, the typicalİ solar maximum from 1785 to 1790 resembles the more modern maximum from 1998 to 2003.…”

“…Our model for dose rates uses the magnetic field model of Goelzer et al [] to deduce the modulation potential of GCRs [e.g., O'Neill , ; Badhwar and O'Neill , ]. The modulation potential allows specification of distribution functions across a range of species with differing numbers of nucleons A and charge state Z .…”

“…Using the modulation potential with the HZETRN model, we then determine GCR‐associated dose rates. The resulting model is used to extrapolate back in time through the space age and to project beyond the current date using a sunspot‐based reconstruction of the heliospheric magnetic field [ Smith et al , ; Goelzer et al , ].…”

Space climate and space weather over the past 400 years: 2. Proxy indicators of geomagnetic storm and substorm occurrence

“…Hence sunspot numbers are used as a proxy for OSF emergence rate. This has been used a great many times since, in conjunction with the OSF continuity equation and/or photospheric flux transport models, in reconstructions (e.g., Solanki et al, 2002;Schrijver et al, 2002;Lean et al, 2002;Usoskin et al, 2002;Lockwood, 2003;Wang et al, 2005;Vieira & Solanki, 2010;Steinhilber et al, 2010;Demetrescu et al, 2010;Goelzer et al, 2013;Wang & Sheeley, 2013;Karoff et al, 2015;Rahmanifard et al, 2017;Asvestari et al, 2017). However, as noted in the area of climate science, regressions with proxies can lead to errors in reconstructions (e.g., Bürger & Cubasch, 2005) and hence it is important to carry out tests on the predictions and to understand the degree of extrapolation used when the reconstructions extend beyond the range of conditions covered by the regressions.…”

An analysis of Alfvén radius based on sunspot number from 1749 to today

“…From this point on ours is a simple application of the theory to the data in an effort to compute the variability of R A with time and the sunspot cycle. Ordinarily, one might not expect a result that varies systematically with the solar cycle if the relevant solar wind parameters varied independently from one another, but the average V SW , N P , and | B | values as measured at 1 AU are seen to fluctuate showing significant long‐term correlations with the sunspot cycle [ McComas et al , , ; Smith and Balogh , ; Connick et al , , ; Schwadron et al , ; Smith et al , ; Goelzer et al , ; N. A. Schwadron et al, Coronal electron temperature in the recent protracted solar minimum, the cycle 24 mini maximum and over centuries, submitted to Journal of Goeophysical Research , 2013].…”