Highly structured slow solar wind emerging from an equatorial coronal hole

  title={Highly structured slow solar wind emerging from an equatorial coronal hole},
  author={Stuart. D. Bale and Samuel T. Badman and J. W. Bonnell and Trevor A. Bowen and David Burgess and Anthony William Case and Cynthia A. Cattell and Benjamin D. G. Chandran and Christopher C. Chaston and C. H. K. Chen and James F. Drake and Thierry Dudok de Wit and Jonathan P. Eastwood and Robert E. Ergun and William M. Farrell and C. Fong and Keith Goetz and Melvyn L. Goldstein and Katherine Amanda Goodrich and Peter R. Harvey and Timothy S. Horbury and Gregory Gershom Howes and Justin C. Kasper and Paul J. Kellogg and James A. Klimchuk and Kelly E. Korreck and Vladimir Krasnoselskikh and S{\"a}m Krucker and Ronan Laker and Davin E. Larson and Robert J. Macdowall and Milan Maksimovi{\'c} and David M. Malaspina and Juan Carlos Mart{\'i}nez-Oliveros and D. J. Mccomas and Nicole Meyer‐Vernet and Michel Moncuquet and Forrest S. Mozer and Tai D. Phan and Marc P. Pulupa and Noureddine Raouafi and Chadi S. Salem and David Stansby and Michael Louis Stevens and Adam Szabo and Marco Velli and Thomas Woolley and John R. Wygant},
During the solar minimum, when the Sun is at its least active, the solar wind1,2 is observed at high latitudes as a predominantly fast (more than 500 kilometres per second), highly Alfvénic rarefied stream of plasma originating from deep within coronal holes. Closer to the ecliptic plane, the solar wind is interspersed with a more variable slow wind3 of less than 500 kilometres per second. The precise origins of the slow wind streams are less certain4; theories and observations suggest that… 
Alfvénic velocity spikes and rotational flows in the near-Sun solar wind
Observations of solar-wind plasma at heliocentric distances of about 35 solar radii reveal an increasing rotational component to the flow velocity of the solar wind around the Sun, peaking at 35 to 50 kilometres per second—considerably above the amplitude of the waves.
The Near-Sun Streamer Belt Solar Wind: Turbulence and Solar Wind Acceleration
<p>The fourth orbit of Parker Solar Probe (PSP) reached heliocentric distances down to 27.9 Rs, allowing solar wind turbulence and acceleration mechanisms to be studied in situ closer to the Sun than
Sub-Alfvénic Solar Wind Observed by the Parker Solar Probe: Characterization of Turbulence, Anisotropy, Intermittency, and Switchback
In the lower solar coronal regions where the magnetic field is dominant, the Alfvén speed is much higher than the wind speed. In contrast, the near-Earth solar wind is strongly super-Alfvénic, i.e.,
Plasma properties, switchback patches, and low α-particle abundance in slow Alfvénic coronal hole wind at 0.13 au
The Parker Solar Probe (PSP) mission presents a unique opportunity to study the near-Sun solar wind closer than any previous spacecraft. During its fourth and fifth solar encounters, PSP had the
Small-scale Flux Emergence, Coronal Hole Heating, and Flux-tube Expansion: A Hybrid Solar Wind Model
Extreme-ultraviolet images from the Solar Dynamics Observatory often show loop-like fine structure to be present where no minority-polarity flux is visible in magnetograms, suggesting that the rate
On Alfvénic Slow Wind: A Journey From the Earth Back to the Sun
Comparative studies of fast and slow solar wind streams performed over the past decades have illustrated several differences between the plasma regimes for these different flows, examples including
The Width, Density, and Outflow of Solar Coronal Streamers
Characterizing the large-scale structure and plasma properties of the inner corona is crucial to understanding the source and subsequent expansion of the solar wind and related space weather effects.
Sharp Alfvénic Impulses in the Near-Sun Solar Wind
Measurements of the near-Sun solar wind by the Parker Solar Probe have revealed the presence of large numbers of discrete Alfvénic impulses with an anti-sunward sense of propagation. These are
Parker Solar Probe observations of suprathermal electron flux enhancements originating from Coronal Hole boundaries
Reconnection between pairs of solar magnetic flux elements, one open and the other a closed loop, is theorised to be a crucial process for both maintaining the structure of the corona and producing
Investigating the Chromospheric Footpoints of the Solar Wind
Coronal holes present the source of the fast solar wind. However, the fast solar wind is not unimodal—there are discrete, but subtle, compositional, velocity, and density structures that


Weaker solar wind from the polar coronal holes and the whole Sun
Observations of solar wind from both large polar coronal holes (PCHs) during Ulysses' third orbit showed that the fast solar wind was slightly slower, significantly less dense, cooler, and had less
Using 3 s plasma and magnetic field data from the Wind spacecraft located in the solar wind well upstream from Earth, we report observations of isolated, pulse-like Alfvénic disturbances in the solar
Heating solar coronal holes
It has been shown that the coronal hole, and the associated high-speed stream in the solar wind, are powered by a heat input of the order of 500,000 ergs/sq cm s, with most of the heat injected in
Coronal Holes
  • S. Cranmer
  • Physics
    Living reviews in solar physics
  • 2009
Measurements of the plasma properties in coronal holes are reviewed and how these measurements are used to reveal details about the physical processes that heat the solar corona and accelerate the solar wind.
Formation of the slow solar wind in a coronal streamer
We have investigated a magnetohydrodynamic mechanism that accounts for several fundamental properties of the slow solar wind, in particular its variability, latitudinal extent, and bulk acceleration.
Large-scale structure of the interplanetary medium
We propose that the coronal source longitude and latitude of solar wind plasma can be estimated within ∼ 10°. Previous writers have argued that the solar wind in the ecliptic should originate near
Probing the Energetic Particle Environment near the Sun
Observations of the near-Sun energetic particle radiation environment over the first two orbits of the Parker Solar Probe find a variety of energetic particle events accelerated both locally and remotely including by corotating interaction regions, impulsive events driven by acceleration near the Sun, and an event related to a coronal mass ejection.
Effect of a Converging Flow at the Streamer Cusp on the Genesis of the Slow Solar Wind
The observation by the Large Angle and Spectrometric Coronagraph (LASCO) instrument on the Solar and Heliospheric Observatory of blobs of plasma generated near the cusp region of the streamer belt
Slow Solar Wind: Observations and Modeling
While it is certain that the fast solar wind originates from coronal holes, where and how the slow solar wind (SSW) is formed remains an outstanding question in solar physics even in the post-SOHO
Predicting the Structure of the Solar Corona and Inner Heliosphere during Parker Solar Probe's First Perihelion Pass
NASA’s Parker Solar Probe (PSP) spacecraft reached its first perihelion of 35.7 solar radii on 2018 November 5. To aid in mission planning, and in anticipation of the unprecedented measurements to be