Authors: Jackson MacTaggart, Susan Lepri, Liang Zhao

During the solar minima of solar cycles 23 and 24, the heliospheric magnetic field and the solar wind were observed to behave much differently than expected. In particular, previous studies showed that the magnetic open flux of the Sun, calculated as the product of the average radial component of the Sun’s magnetic field and the squared radial distance from the Sun, was observed to have decreased along with observed changes in solar wind streams. This was in contrast to the standing theory that the “baseline” of the solar minima should require the magnetic open flux to remain constant across the minima. In this work, we examine these parameters across 3 solar minimums in cycles 23, 24, and 25. Using measurements of the heliospheric magnetic field and solar wind proton dynamic data (e.g., proton speed, density, pressure, and temperature) and heavy ion composition (including charge state and elemental abundances) from ACE, Ulysses, and Solar Orbiter, we show that these parameters, with special focus on the magnetic open flux, have evolved differently with the solar cycle. In addition, we investigate the evolution of the coronal holes and active regions observed by remote sensing during each Carrington rotation during the past three solar cycles as provided by the SOHO/EIT,  SDO AIA, and STEREO SECCHI/EUVI instruments, and evaluate the differences in their evolutions across the solar cycles. We will summarize our results and discuss their implications on  validating different solar dynamo models.