The upper atmosphere of the Sun is dominated by plasma filled magnetic loops (coronal loops) whose temperature and pressure vary over a wide range. The appearance of coronal loops follows the emergence of magnetic flux, which is generated by dynamo processes inside the Sun. Emerging flux regions (EFRs) appear when magnetic flux bundles emerge from the solar interior through the photosphere and into the upper atmosphere (chromosphere and the corona). The characteristic feature of EFR is the -shaped loops (created by the magnetic buoyancy/Parker instability), they appear as developing bipolar sunspots in magnetograms, and as arch filament systems in . EFRs interact with pre-existing magnetic fields in the corona and produce small flares (plasma heating) and collimated plasma jets. The GIFs above show multiple energetic jets in three different wavelengths. The light has been colorized in red, green and blue, corresponding to three coronal temperature regimes ranging from ~0.8Mk to 2MK. 

Image Credit: SDO/U. Aberystwyth

Plasma: Your Universe Isn’t Made of What You Think

If I asked you to name the fundamental states of matter, more than likely you’d reel off solid, liquid, and gas. But if you’re a bit savvier, you’d know that those three aren’t the only states that matter can take—in fact, they’re not even the most abundant.

Plasma is the fourth fundamental state of matter. It’s a lot like a gas, except its atoms have been ionised: the electrons have been stripped from their nuclei, creating a sea of distinct, positively and negatively charged particles. In gases, electrons are bound to their nuclei, but in plasma, they’re free to move about. For this reason, plasmas are often called ionised (or electrically charged) gases.

Plasma can be created by heating gases or by subjecting them to strong electromagnetic fields. Though it doesn’t naturally make up the things we see, eat, breathe or live in, man-made plasmas can be found quite readily on Earth in fluorescent light bulbs and neon signs, which use electricity to ionise the gas inside of them, creating glowing plasma. Very hot flames and lightning are also examples of plasma. But most significantly, plasmas are naturally found in stars, thanks to their incredibly hot temperatures, and in enormous gas clouds in the spaces between galaxies, often stretched into huge webs and filaments. Because of this, plasma is the most abundant state of matter in the universe.

Fun fact: the states of matter don’t end with plasma. Bose–Einstein condensates and neutron-degenerate matter also exist, which are only observable in extreme conditions, as well as a couple of theoretical states.


Sunspots are dark regions on the solar surface that contain complex arrangements of strong  localized magnetic fields and are often accompanied by intense solar activity (such as solar flares, coronal mass ejections), especially during the solar maximum. The dark central region of  a sunspot is called the umbra. It contains nearly vertically oriented magnetic flux tubes, which suppress the convective heat transfer. These magnetic flux tubes emerge to the solar surface at the activity belt (±30◦ latitude) and form bipolar sunspot pairs. Due to the energy deficit the inner part of the sunspot is about 1,500 degrees cooler than the surrounding quiet Sun, therefore it appears darker against the hotter and brighter background. The semi-dark outer section of the sunspot – the penumbra is surprisingly complex. It contains bright and dark filamentary structures with varying magnetic field inclinations. The inclination of the magnetic field plays a significant role in the formation of radial plasma currents, known as the Evershed flow. In the presence of increasing magnetic inclination the granular cells become elongated magnetoconvective rolls

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Image Credit: The Royal Swedish Academy of Sciences, Vasco M.J. Henriques/Luc Rouppe van der Voort


Make Your Own Plasma Cutter!

Build your own tiny metal-slicing plasma cutter at home. All it takes is a pencil lead, a couple of batteries, some alligator clips and aluminum foil. The National Science Foundation series Little Shop Of Physics presents a simple science experiment anyone can complete to learn about this common manufacturing process. 

While this little device is only powerful enough to slice through foil, industrial-sized units can cut through 6-inch-thick steel plates. Big or small, the process works by sending an electrical arc through gas to ionize it and turn it into a super-hot plasma.  


For those of us who are Earthbound, it’s easy to think of liquids and gases as being the most common fluids. But plasma–the fourth state of matter–is a fluid as well. Plasmas are essentially ionized gases, which, thanks to their freely flowing electrons, are electrically conductive and sensitive to magnetic fields. Their motions are described by a combination of the Navier-Stokes equations–the usual equations of motion for a fluid–and Maxwell’s equations–the equations governing electricity and magnetism. Studies of plasma motion often fall under the subject of magnetohydrodynamics and can include topics like planetary auroras, sunspots, and solar flares. (Video credit: SciShow)


Two views of an X-class solar flare on Sept. 10, 2014. IRIS focuses on the lower regions of the sun’s atmosphere, while the SDO imagery shows a region that is hotter and typically slightly above that. 

The IRIS video shows a dark sunspot in the upper right, a magnetically complex  region observed on the sun’s surface. SDO, on the other hand, shows what’s happening above that – giant magnetic loops rise up off the surface.  As the flare begins, crisp bright lines show up moving across the IRIS data, showing where material begins to be heated with the onset of the flare. Some of this imagery appears in the SDO side as well, but so do many other features and brightenings.  It is only by comparing the two movies that one can tease out what’s happening at the lower temperatures – likely to be in the lower atmosphere – versus what is happening higher up.

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Credit: NASA/LMSAL/Wiessinger


Plasma, The Most Common Phase of Matter in the Universe

Get to know plasma, the most common, but probably least understood, phase of matter in the universe!