Our Tempestuous Sun, Part 2.

Our tempermental and stormy sun, forged from a violent birth, is an electrically charged ball of gas, called plasma, with three inner and outer layers.  Plasma is constantly churning and convecting through the sun’s inner layers, and some of it escapes to the photosphere and emits visible light through granulations on the sun’s surface that we observe with telescopes from earth, see Figure 1.  However, the sun is more than just a ball of gas.  The sun is electric and magnetic. It is made of material that moves in concert with the laws of electromagnetism…”[1]

[1] https://www.nasa.gov/feature/goddard/2016/understanding-the-magnetic-sun

Figure 1 Credit: Trace/Standford-Lockheed Institute for Space Research/NASA

What that means is the interactions of the moving, positively charged protons, and negatively charged electrons (particles) in the sun, create electro-magnetism and electric fields.[1]  The movement, therefore, of the sun’s charged particles – plasma – within its inner layers create electric currents that create electro-magnetic fields – the dynamo effect.[2] 

What Is the Solar Atmosphere?  The sun’s atmosphere is called the magnetosphere and consists of its outer layers: the photosphere, chromosphere, and corona.  The photosphere expands approximately 250 miles (400 kms) above the sun’s surface.[3]  From there solar weather, created by the sun’s internal dynamo, streams into outerspace.  The chromosphere and corona emit white light and can be seen during a solar eclipse when the light of the photosphere is blocked out. 

[1] “Magnetic fields are produced by moving electric charges.”  Magic of Magnetism, Museum of Science, https://ece.northeastern.edu/fac-ece/nian/mom/magfields.html

[2] NASA, Solar Physics, Marshall Space Flight Center, The Solar Dynamo, Author Dr. David H. Hathaway, https://solarscience.msfc.nasa.gov/dynamo.shtml; updated 2011 August 14.

[3] NASA Layers of the Sun, Ibid.

Figure 2 shows a view of the sun’s chromosphere and corona taken during a solar eclipse, revealing the corona as “a pearly-white halo around the sun” and the chromosphere as a “thin, crimson ring around the edge of the sun.”[1]  Solar scientists also use filters to view the sun’s atmosphere, notably the NASA and ESA joint LASCO (Large Angle and Spectrometric Coronagraph) mission.  The coronograph is “a telescope that is designed to block light coming from the solar disk, in order to see the extremely faint emission from the region around the sun, called the corona.”[2]  

[1].https://www.researchgate.net/figure/Two-views-of-the-Sun-during-a-total-solar-eclipse-Left-the-pink-chromosphere-is_fig1_26502057; H-alpha () is a deep-red visible spectral line of the hydrogen atom with a wavelength of 656.28 nm in air and 656.46 nm in vacuum, https://en.wikipedia.org/wiki/H-alpha

[2] Space Weather Prediction Center, National Oceanic and Atmospheric Administration (NOAA), https://www.swpc.noaa.gov/products/lasco-coronagraph

Figure 2, Image Credkt Luc Viatour

What Is Solar Weather?  Briefly, solar or space weather is directly related to the sun’s magnetism.  Emissions from the sun’s surface due to convection – stirring, moving, churning – of its plasma are carried into space along the sun’s magnetic fields.  The interaction of positively charged protons and negatively charged electrons during fusion,[1] where the heavier protons try to prevent the lighter electrons from escaping,[2] generates the sun’s magnetic fields that are carried into space.

[1] How does the sun’s magnetic field work? Dave Mccomas, http://ibex.swri.edu/students/How_does_the_Sun.shtml

[2] IowaNow, “Physicists led by University of Iowa more fully describe sun’s electric field” By Richard C. Lewis 2021, NASA Southwest Research Institute, IBEX Interstellar Boundary Explorer https://now.uiowa.edu/2021/07/physicists-led-university-iowa-more-fully-describe-suns-electric-field

There they interact with planetary bodies and space itself.  NASA, ESA and other international agencies have a “fleet of solar observatories”[1] that observe solar weather events using ground based telescopes and satellites like the the solar orbiter.  However, the sun’s magnetic fields are invsible to our eyes.  If the sun’s magnetic fields are invisble to the human eye how do we know they exist ?  We’ll tell you all about it in the next issue.  See you then.   

[1] https://solarsystem.nasa.gov/solar-system/sun/exploration/?page=0&per_page=10&order=launch_date+desc%2Ctitle+asc&search=&tags=Sun&category=33


Figure 3 Image Credit: NOAA and SWPC