Speaker: Ben Lynch
Affiliation: UCLA, EPSS

Abstract:
The eleven-year solar activity cycle manifests itself in a variety of spectacular and interdependent ways. For example, the spatiotemporal distribution of the emergence of bipolar active regions (ARs) impart a spatiotemporal dependence to the response and re-configuration of overlying large-scale, closed-flux helmet streamer belt. Additionally, specific AR--background field configurations can arise that form new, intermediate-scale closed-flux systems surrounded by single polarity open fields, such as coronal pseudostreamers, which also inherit the underlying solar cycle-dependence of their photospheric flux distributions. The global magnetic structure of the solar corona, in turn, determines the entire solar wind stream and magnetic sector structure of the inner heliosphere. The cusp region of the coronal helmet streamer belt extends into a dense, slow solar wind plasma sheet that contains the heliospheric current sheet (HCS), separating the open fields of opposite polarity. The equivalent heliospheric extension of pseudostreamer outflows along the outer spine-line or spine-fan, result in slow, plasma-sheet like solar wind embedded in a single open field polarity.
In this talk , I will present an overview of the ways in which coronal magnetic field topology, open-closed flux system boundary layers, and their dynamic evolution can determine the resulting solar wind properties and structure of the inner heliosphere. As an illustrative example, I will discuss recent remote-sensing and in-situ observations made by Parker Solar Probe (PSP) in the context of the Casillas et al. [2026] magnetohydrodynamic simulation results. For example, the PSP Encounter 24 observations appear to have captured certain aspects of the Casillas et al. scenario of a global-scale pseudostreamer--to--helmet streamer transition and the generation of outflow transients associated with the opening-up (and closing-down) of a large-scale pseudostreamer flux system which creates (or destroys) the parasitic-polarity solar wind streams and their associated HCSs.

Submitted by: Omar Abuassaf (oabuassaf@epss.ucla.edu)