The Whole Heliosphere and Planetary Interactions (WHPI) is an international initiative to study the most recent solar minimum and its impact on the interconnected solar‐heliospheric‐planetary system by facilitating and encouraging interdisciplinary activities. Particular WHPI science foci include the global connected structure of the heliosphere and planetary space environments/atmospheres, the origins and impacts of high‐speed solar wind streams, coronal mass ejections from Sun‐to‐Heliopause, and comparative solar minima. This is achieved through a series of coordinated observing campaigns, including Parker Solar Probe perihelia, and scientific virtual interactions including a dedicated workshop where observers and modelers gathered to discuss, compare, and combine research results. This introduction sets the scene for the WHPI interval, placing it into the context of prior initiatives and describing the overall evolution of the system between 2018 and 2020. Along with the accompanying articles, it presents a selection of key scientific results on the interconnected solar‐heliospheric‐planetary system at solar minimum.
The Whole Heliosphere and Planetary Interactions initiative was established to leverage relatively quiet intervals during solar minimum to better understand the interconnectedness of the various domains in the heliosphere. This study provides an expansive mosaic of observations spanning from the Sun, through interplanetary space, to the magnetospheric response and subsequent effects on the ionosphere‐thermosphere‐mesosphere (ITM) system. To accomplish this, a diverse set of observational datasets are utilized from 2019 July 26 to October 16 (i.e., over three Carrington rotations, CR2220, CR2221, and CR2222) with connections of these observations to the more focused studies submitted to this special issue. Particularly, this study focuses on two long‐lived coronal holes and their varying impact in sculpting the heliosphere and driving of the magnetospheric system. As a result, the evolution of coronal holes, impacts on the inner heliosphere solar wind, glimpses at mesoscale solar wind variability, magnetospheric response to these evolving solar wind drivers, and resulting ITM phenomena are captured to reveal the interconnectedness of this system‐of‐systems.
more » « less- Award ID(s):
- 2002574
- PAR ID:
- 10423579
- Publisher / Repository:
- DOI PREFIX: 10.1029
- Date Published:
- Journal Name:
- Journal of Geophysical Research: Space Physics
- Volume:
- 128
- Issue:
- 6
- ISSN:
- 2169-9380
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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http://csem.engin.umich.edu/mswim2d/ . The web interface extracts output at desired locations and times. In addition to solar wind ions, the model includes neutrals coming from the interstellar medium to reproduce the slowing of the solar wind in the outer heliosphere and to extend the utility of the model to larger radial distances. The inclusion of neutral hydrogen is critical to recreating the solar wind accurately outside of ∼4 au. The inner boundary is filled by interpolating and time-shifting in situ observations from L1 and STEREO spacecraft when available. Using multiple spacecraft provides a more accurate boundary condition than a single spacecraft with time shifting alone. Validations of MSWIM2D are performed using MAVEN and New Horizons observations. The results demonstrate the efficacy of this model to propagate the solar wind to large distances and obtain practical, useful solar wind predictions. For example, the rms error of solar wind speed prediction at Mars is only 66 km s−1and at Pluto is a mere 25 km s−1. -
This paper outlines key scientific topics that are important for the development of solar system physics and how observations of heavy ion composition can address them. The key objectives include, 1) understanding the Sun’s chemical composition by identifying specific mechanisms driving elemental variation in the corona. 2) Disentangling the solar wind birthplace and drivers of release by determining the relative contributions of active regions (ARs), quiet Sun, and coronal hole plasma to the solar wind. 3) Determining the principal mechanisms driving solar wind evolution from the Sun by identifying the importance and interplay of reconnection, waves, and/or turbulence in driving the extended acceleration and heating of solar wind and transient plasma. The paper recommends complementary heavy ion measurements that can be traced from the Sun to the heliosphere to properly connect and study these regions to address these topics. The careful determination of heavy ion and elemental composition of several particle populations, matched at the Sun and in the heliosphere, will permit for a comprehensive examination of fractionation processes, wave-particle interactions, coronal heating, and solar wind release and energization that are key to understanding how the Sun forms and influences the heliosphere.more » « less
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Abstract The variability of helium abundance in the solar corona and the solar wind is an important signature of solar activity, solar cycle, and solar wind sources, as well as coronal heating processes. Motivated by recently reported remote-sensing UV imaging observations by Helium Resonance Scattering in the Corona and Heliosphere payload sounding rocket of helium abundance in the inner corona on 2009 September 14 near solar minimum, we present the results of the first three-dimensional three-fluid (electrons, protons, and alpha particles) model of tilted coronal streamer belt and slow solar wind that illustrates the various processes leading to helium abundance differentiation and variability. We find good qualitative agreement between the three-fluid model and the coronal helium abundance variability deduced from UV observations of streamers, providing insight on the effects of the physical processes, such as heating, gravitational settling, and interspecies Coulomb friction in the outflowing solar wind that produce the observed features. The study impacts our understanding of the origins of the slow solar wind.
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Abstract The McIntosh Archive consists of four solar cycles (SC20–23) of synoptic maps of solar features (magnetic polarities, coronal holes, filaments, sunspots, plage) that were produced by Patrick McIntosh and his cartographers. In this paper we present the full Archive for the first time and find a hemispheric pattern of coronal hole polarity reflecting the Hale sunspot polarity pattern. In addition, we present a supplemental set of related maps created for the 2019–2020 solar minimum in support of the Whole Heliosphere and Planetary Interactions (WHPI) interval. To facilitate this addition, we cross calibrate EUV and He‐I 10,830 Å coronal holes and study differences between the WHPI solar minimum and the earlier minima in the main Archive. We find, first, that the visibility of coronal holes in EUV introduces a bias toward larger counts of low‐latitude coronal holes near solar minimum. However, the estimated lifetimes (in Carrington Rotations) of coronal hole complexes are unaffected by this fragmentation, and we find the longest‐lived low‐latitude coronal holes occurred during the 2008–2009 solar minimum, with 2019–2020 solar minimum lifetimes not far behind. In this way, we consider the large‐scale organization of solar magnetic fields between solar minima and study each solar minimum in the context of its solar cycle.
