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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. Plain Language Summary: The field of Heliophysics research spans a large range of plasma regimes and disciplines that are all linked through the complex interactions each system has with one another. To better explore the interconnected nature of the heliosphere, this study combines observations from across the sub‐domains of Heliophysics to construct snapshots of the Sun, solar wind, and the magnetospheric and ionospheric systems at Earth over three revolutions of the Sun. This allows for a unique vantage point to put these systems in perspective of one another and understand how they impact one another. Key Points: The evolution and impacts of two coronal holes are investigated over three Carrington rotationsThe evolution of the coronal hole led to changes in the solar wind throughout the inner solar systemSubsequent geospace response differed with each passage due to both changes in the solar wind and preconditioning within the systems [ABSTRACT FROM AUTHOR]

The poleward boundary intensification (PBI) is a common appearance at the poleward boundary of the auroral bulge and auroral oval. The PBI presented here occurred during the expansion phase of a small substorm with an auroral surge power of 6.5 GW. The auroral power of the PBI (1.1 GW) was ~17% of this value. The largest powers above the nominal auroral acceleration region at 5 RE geocentric were carried by Alfvén waves (1.7 GW) and Alfvénic electrons (0.7 GW), sufficient to account for the conjugate PBI auroral power. In contrast, the conjugate quasistatic, field‐aligned current power (<0.3 GW) was not sufficient. Observed correlation between quasiperiodic Alfvénic pulses and auroral modulations strengthens our conclusion that the electromagnetic magnetosphere‐ionosphere coupling of the PBI was dominantly Alfvénic, as opposed to electrostatic, thus causing Alfvénic aurora. Key Points: Quasiperiodic magnetotail Alfvén wave pulses drive correlated PBI luminosity modulationsMagnetosphere‐ionosphere coupling of PBI is dominantly Alfvénic, as opposed to electrostaticPBI power estimates are compared with streamer power estimates [ABSTRACT FROM AUTHOR]

Two sequences of five high‐speed solar wind stream/corotating interaction region (HSS/CIR) events were observed at 1 AU in December 2007–2008. These two HSS/CIR sequences had opposite magnetic polarities, and they originated from two persistent low‐latitude coronal holes with corresponding polarities. Each HSS/CIR event triggered a geomagnetic storm and strong high‐latitude activity. We follow the evolution of the properties and geomagnetic effects of the two sequences and find that the sequence with negative interplanetary magnetic field polarity (toward sector) develops systematically a more negative Bz(GSM) component and becomes relatively more geoeffective when moving from winter solstice in 2007 to spring equinox in 2008. On the other hand, the sequence with positive polarity (away sector) develops systematically a less negative Bz(GSM) component and becomes relatively less geoeffective. These changes allow the first detailed monitoring of the turning on of the Russell‐McPherron effect when moving from solstice to equinox and the development of the related changes in high‐latitude geomagnetic activity and geomagnetic storms. Key Points: We study two sequences of stable high‐speed streams with opposite polarities in 2007–2008, locate their sources and follow their effectsIMF Bz(GSM)‐Bz(GSE) difference decreases (increases) systematically in the negative (positive) polarity sequence from solstice to equinoxWe quantify the effect of this turning on of the Russell‐McPherron mechanism to high‐latitude geomagnetic activity and geomagnetic storms [ABSTRACT FROM AUTHOR]