A Quarter Century of<i>Wind</i>Spacecraft Discoveries

Wilson, L. B.; Brosius, A. L.; Gopalswamy, N.; Nieves‐Chinchilla, Teresa; Szabó, Á.; Hurley, K.; Phan, T. D.; Kasper, J. C.; Lugaz, Noé; Richardson, I. G.; Chen, Christopher H. K.; Verscharen, Daniel; Wicks, Robert T.; TenBarge, Jason

doi:10.1029/2020rg000714

Cited by 86 publications

(64 citation statements)

References 529 publications

(945 reference statements)

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“…Our primary results are drawn from the MMS (Burch et al., 2016). We also used data from both the Wind (Harten & Clark, 1995; Wilson, Brosius, et al., 2021) and ARTEMIS (Angelopoulos, 2010) spacecraft to establish the prevailing interplanetary conditions. The main analysis relies on MMS data from the Fast Plasma Investigation (FPI) (Pollock et al., 2016), Fluxgate Magnetometer (FGM) (Russell et al., 2016), and electric field instrumentation (Ergun et al., 2016; Lindqvist et al., 2016; Torbert et al., 2016).…”

Section: Datamentioning

confidence: 99%

Evaluating the deHoffmann‐Teller Cross‐Shock Potential at Real Collisionless Shocks

et al. 2021

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Shock waves are common in the heliosphere and beyond. The collisionless nature of most astrophysical plasmas allows for the energy processed by shocks to be partitioned amongst particle sub‐populations and electromagnetic fields via physical mechanisms that are not well understood. The electrostatic potential across such shocks is frame dependent. In a frame where the incident bulk velocity is parallel to the magnetic field, the deHoffmann‐Teller frame, the potential is linked directly to the ambipolar electric field established by the electron pressure gradient. Thus measuring and understanding this potential solves the electron partition problem, and gives insight into other competing shock processes. Integrating measured electric fields in space is problematic since the measurements can have offsets that change with plasma conditions. The offsets, once integrated, can be as large or larger than the shock potential. Here we exploit the high‐quality field and plasma measurements from NASA's Magnetospheric Multiscale mission to attempt this calculation. We investigate recent adaptations of the deHoffmann‐Teller frame transformation to include time variability, and conclude that in practice these face difficulties inherent in the 3D time‐dependent nature of real shocks by comparison to 1D simulations. Potential estimates based on electron fluid and kinetic analyses provide the most robust measures of the deHoffmann‐Teller potential, but with some care direct integration of the electric fields can be made to agree. These results suggest that it will be difficult to independently assess the role of other processes, such as scattering by shock turbulence, in accounting for the electron heating.

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Section: Datamentioning

confidence: 99%

Evaluating the deHoffmann‐Teller Cross‐Shock Potential at Real Collisionless Shocks

et al. 2021

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“…2 and 3. Figure 2 shows in situ observations from the Wind spacecraft (Wilson et al 2021) of a clear ICME that consists of a "magnetic cloud" (in the interval between the vertical brown lines) characterised by an enhanced magnetic field magnitude and a smooth rotation of the magnetic field through a large angle, suggestive of a flux-rope-like magnetic field structure, and a low proton temperature (as discussed by e.g., Burlaga et al 1981;Klein and Burlaga 1982;Lepping et al 1990). This follows a shock (vertical blue line) and a sheath region between the shock and magnetic cloud.…”

Section: Evidence For Stealth Cmes: An Observational Perspectivementioning

confidence: 99%

Understanding the Origins of Problem Geomagnetic Storms Associated with “Stealth” Coronal Mass Ejections

et al. 2021

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Geomagnetic storms are an important aspect of space weather and can result in significant impacts on space- and ground-based assets. The majority of strong storms are associated with the passage of interplanetary coronal mass ejections (ICMEs) in the near-Earth environment. In many cases, these ICMEs can be traced back unambiguously to a specific coronal mass ejection (CME) and solar activity on the frontside of the Sun. Hence, predicting the arrival of ICMEs at Earth from routine observations of CMEs and solar activity currently makes a major contribution to the forecasting of geomagnetic storms. However, it is clear that some ICMEs, which may also cause enhanced geomagnetic activity, cannot be traced back to an observed CME, or, if the CME is identified, its origin may be elusive or ambiguous in coronal images. Such CMEs have been termed “stealth CMEs”. In this review, we focus on these “problem” geomagnetic storms in the sense that the solar/CME precursors are enigmatic and stealthy. We start by reviewing evidence for stealth CMEs discussed in past studies. We then identify several moderate to strong geomagnetic storms (minimum Dst $< -50$ < − 50 nT) in solar cycle 24 for which the related solar sources and/or CMEs are unclear and apparently stealthy. We discuss the solar and in situ circumstances of these events and identify several scenarios that may account for their elusive solar signatures. These range from observational limitations (e.g., a coronagraph near Earth may not detect an incoming CME if it is diffuse and not wide enough) to the possibility that there is a class of mass ejections from the Sun that have only weak or hard-to-observe coronal signatures. In particular, some of these sources are only clearly revealed by considering the evolution of coronal structures over longer time intervals than is usually considered. We also review a variety of numerical modelling approaches that attempt to advance our understanding of the origins and consequences of stealthy solar eruptions with geoeffective potential. Specifically, we discuss magnetofrictional modelling of the energisation of stealth CME source regions and magnetohydrodynamic modelling of the physical processes that generate stealth CME or CME-like eruptions, typically from higher altitudes in the solar corona than CMEs from active regions or extended filament channels.

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“…The dataset is combined 8 from in situ data measured by multiple spacecraft. The ones that serve as sources of the electron density data for 2006-2017 are the ACE (Stone et al 1998) and Wind (Wilson III et al 2021).…”

Section: In Situ Solar Wind Measurementsmentioning

confidence: 99%

Improving the Solar Wind Density Model Used in Processing of Spacecraft Ranging Observations

Aksim,

Pavlov

2021

Preprint

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Solar plasma as a cause of radio signal delay has been playing an important role in solar and planetary science. Early experiments studying the distribution of electrons near the Sun from spacecraft ranging measurements were designed so that the radio signal was passing close to the Sun. At present, processing of spacecraft tracking observations serves a different goal: precise (at meter level) determination of orbits of planets, most importantly Mars. Solar plasma adds a time-varying delay to those observations, which is, in this case, unwanted and must be subtracted prior to putting the data into planetary solution. Present planetary ephemeris calculate the delay assuming symmetric stationary power-law model of solar plasma. The present work, based on a custom variant of the EPM lunar-planetary ephemeris, raises the question of accuracy and correctness of that assumption and examines alternative models based on in situ data provided by OMNI and on the ENLIL numerical model of solar wind.

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A Quarter Century ofWindSpacecraft Discoveries

Abstract: The objective of the ISTP program was to study the origin of solar variability and activity, the transport of manifestations of that activity to the Earth via plasma processes, and the cause-and-effect relationships between that time varying energy transport and the near-earth environment.

Cited by 86 publications

References 529 publications

Evaluating the deHoffmann‐Teller Cross‐Shock Potential at Real Collisionless Shocks

Evaluating the deHoffmann‐Teller Cross‐Shock Potential at Real Collisionless Shocks

Understanding the Origins of Problem Geomagnetic Storms Associated with “Stealth” Coronal Mass Ejections

Improving the Solar Wind Density Model Used in Processing of Spacecraft Ranging Observations

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