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Solar Cycle Variation of the Heliospheric Magnetic Flux, Solar Wind Flux and Galactic Cosmic Rays Charles W. Smith, Nathan A. SchwadronKen G. McCracken, and Molly L. Goelzer April 2014 Meeting of the NESSC
There is a history to these ideas: • The heliospheric magnetic flux by: • Nancy Crooker • Matt Owens • Mike Lockwood • Reconstruction of the HMF from paleogenic data: • Ken McCracken, Leif Svalgaard, Matt Owens and Mike Lockwood
There is Ample Evidence of Weak Solar Wind and HMF over the Recent Solar Minimum • McComas et al., GRL, 35, L18103, 2008. • Ed Smith & Balogh, GRL, 35, L22103, 2008. • Connick et al., ApJ, 695, 357, 2009. • Connick et al., ApJ, 727, 8, 2011. • McComas et al., ApJ, 779, 2, 2013. • + many papers on the solar side of the equation
I’ll be showing work from: • Schwadron & McComas, ApJL, 686, L33, 2008. • Schwadron et al., ApJ, 722, L132, 2010. • Connick et al., ApJ, 727, 8, 2011. • Smith et al., ApJ, 775, 59, 2013. • Goelzer et al., JGR, 118, 7525, 2013. • Smith et al., Space Weather, submitted.
Caveat • Schwadron et al. (2010) theory uses the measured injection of magnetic flux due to CMEs. • Measured by Owens (2008). • It does not use the volume-integrated measured injection of magnetic field line intensities. • In other words, there are fluctuations relative to the mean that do not contribute to the net flux.
Schwadron et al. (ApJ, 722, L132, 2010)Decline and Recovery of IMF 20 d 6 yr 2.5 yr 1/2 1013 Wb Owens & Crooker (2002)
Driving function f departs slightly from the observations of CME eruption rate since CMEs continue as sunspots zero. However, CMEs appear weak during these years. This suggests a study I’d like to do. Theory predicts BP and not |B|, which is consistently larger. Theory follows observations remarkably well. Parker field rises immediately with CME injection of new flux. Parker field falls more slowly than flux injection rate.
Goelzer et al. - HMF 1749 to Today Prediction of the coming minimum. Attach Dalton Minimum SSN 1805 onward.
Schwadron & McComas (2008) Nathan’s view is that the magnetic field controls the solar wind output. We will show that the magnetic field can be viewed as an injection process via CMEs and an ejection process based on reconnection.
Smith et al. (Space Weather, submitted) Caballero-Lopez et al (2004) McCracken (2007)
Smith et al. (Space Weather, submitted) Using established ideas we can compute the GCR spectra for various solar minimum conditions: Gleeon & Axford (1968). The lower the sunspot number the higher the GCR intensity. Past Grand Minima show strongly higher GCR rates than the modern space age.
Summary • We can make pretty good predictions of the HMF flux, solar wind proton flux, and galactic cosmic ray intensity based on the history of sunspot number. • However: • Is flux content of CMEs independent of solar cycle? • I think we know it’s not! • Is there a floor to the HMF flux during deep solar minima?