The Properties of the Solar Corona and Its Connection to the Solar Wind

  title={The Properties of the Solar Corona and Its Connection to the Solar Wind},
  author={Steven R. Cranmer and Amy R. Winebarger},
  journal={Annual Review of Astronomy and Astrophysics},
The corona is a layer of hot plasma that surrounds the Sun, traces out its complex magnetic field, and ultimately expands into interplanetary space as the supersonic solar wind. Although much has been learned in recent decades from advances in observations, theory, and computer simulations, we still have not identified definitively the physical processes that heat the corona and accelerate the solar wind. In this review, we summarize these recent advances and speculate about what else is… 

Figures and Tables from this paper

The explanation for the mysterious hot solar corona

The coronal heating has remained a puzzle for decades since its observation in 1940. Several space missions have been planned to resolve this conundrum in the past and many more intend to target this

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.,

λ And: a post-main-sequence wind from a solar-mass star

We investigate the wind of λ And, a solar-mass star that has evolved off the main sequence becoming a subgiant. We present spectropolarimetric observations and use them to reconstruct the surface

The Sun’s dynamic extended corona observed in extreme ultraviolet

The “middle corona” is a critical transition between the highly disparate physical regimes of the lower and outer solar corona. Nonetheless, it remains poorly understood due to the difficulty of

Physical Characteristics of Unstructured Coronal Clouds

Active regions in the inner solar corona, when observed in X-ray emission, consist of bright, hot loops surrounded by unstructured clouds. The emission from the clouds extends to a height of ≈4–5 ×

Alpha particle thermodynamics in the inner heliosphere fast solar wind

Context. Plasma processes occurring in the corona and solar wind can be probed by studying the thermodynamic properties of different ion species. However, most in situ observations of positive ions

Structure of the Solar Atmosphere: A Radio Perspective

Solar radio emission has been providing information about the Sun for over half a century. In order to fully exploit this information, one needs to have a broader view of the solar atmosphere, which

Geometry of Magnetic Fluctuations near the Sun from the Parker Solar Probe

Solar wind magnetic fluctuations exhibit anisotropy due to the presence of a mean magnetic field in the form of the Parker spiral. Close to the Sun, direct measurements were not available until the

The evolution of the solar wind

  • A. Vidotto
  • Physics, Geology
    Living reviews in solar physics
  • 2021
It is argued that studying exoplanetary systems could open up new avenues for progress to be made in the authors' understanding of the evolution of the solar wind, as well as implications of the evolved solar wind on the evolving Earth and other solar system planets.

Heating Rates for Protons and Electrons in Polar Coronal Holes: Empirical Constraints from the Ultraviolet Coronagraph Spectrometer

Ultraviolet spectroscopy of the extended solar corona is a powerful tool for measuring the properties of protons, electrons, and heavy ions in the accelerating solar wind. The large coronal holes



Coronal Expansion and Solar Wind

I History and Background.- I.1 Introduction.- I.2 Indirect Evidence for the Existence of the Solar Wind.- I.3 The Extension of the Solar Corona into Interplanetary Space.- I.4 The Expansion of the

Broadening of the differential emission measure by multi-shelled and turbulent loops

Context. Broad differential emission measure (DEM) distributions in the corona are a sign of multi-thermal plasma along the line-of-sight. Traditionally, this is interpreted as evidence of

Solar Wind Turbulence Studies Using MMS Fast Plasma Investigation Data

Studies of solar wind turbulence traditionally employ high-resolution magnetic field data, but high-resolution measurements of ion and electron moments have been possible only recently. We report the

Implications of Recent Stellar Wind Measurements

  • B. Wood
  • Physics
    Journal of Physics: Conference Series
  • 2018
Very recent measurements of stellar winds are used to update relations between winds and coronal activity. New wind constraints include an upper limit of Ṁ < 0.1 Ṁ⊙ for τ Ceti (G8 V), derived from a

Physics of the Solar Corona: An Introduction with Problems and Solutions

Thermal Radiation.- Hydrostatics.- Hydrodynamics.- Magnetic Fields.- Magneto-Hydrodynamics (MHD).- MHD Oscillations.- Propagating MHD Waves.- Coronal Heating.- Magnetic Reconnection.- Particle

The Solar Corona

Physics of the Solar Corona By I. S. Shklovskii. Second edition. Translated by L. A. Fenn. Translation edited by A. Beer. Additional material translated and edited by A. J. Meadows. (International


Course Description: This course is designed to provide a basic introduction to some of the major philosophical traditions of China, India, and Japan. In this introduction, we will read a variety of


  • Rev. Astron. Astrophys. 24:377–420 Echim MM, Lemaire J, Lie-Svendsen Ø. 2011. Surveys in Geophys. 32:1–70
  • 1986

VA, and this ends up giving a result equivalent to the line-tied cascade case of Dmitruk

  • 1999

Nature 522:188–191 Antiochos SK, Mikić Z, Titov VS, Lionello R, Linker JA

  • 2011. Ap. J. 731:112 Antolin P, Rouppe van der Voort L. 2012. Ap. J. 745:152 Arge CN, Pizzo VJ. 2000. J. Geophys. Res. 105:10465–10480 Aschwanden MJ. 2006. Physics of the Solar Corona: An Introduction with Problems and Solutions, 2nd ed. Chich-
  • 2015