![Alfven-wave double-layer](https://www.plasma-universe.com/wp-content/uploads/Alfven-wave-double-layer.gif)
A cluster of double layers forming in an Alfvén wave, about a sixth of the distance from the left. Source
Alfvén wave
![Heliospheric current sheet](https://www.plasma-universe.com/wp-content/uploads/Heliospheric-current-sheet_edit-300x210.jpg)
The heliospheric current sheet results from the influence of the Sun's rotating magnetic field on the plasma in the interplanetary medium [1]. The wavy spiral shape has been likened to a ballerina's skirt, and carries a tiny 10-10 A/m2
Astrophysical plasma
![Aurora Borealis](https://www.plasma-universe.com/wp-content/uploads/Polarlicht_2-300x195.jpg)
The Aurora Borealis, or Northern Lights, shines above Bear Lake
Wikimedia Commons picture of the year, 2006 Eielson Air Force Base, Alaska Source
Aurora
![Hale Bopp with 3 tails](https://www.plasma-universe.com/wp-content/uploads/Hale-bopp-3-tails-279x300.png)
Comet Hale-Bopp showing three tails: (1) red: water ions (2) yellow: sodium atoms (3) blue: dust tail. Photo credit: J. Wilson, J. Baumgardner, M. Mendillo (Boston University)[1]
Comet
![Giotto Halley jets](https://www.plasma-universe.com/wp-content/uploads/Giotto-halley-jets-295x300.jpg)
Jets emanating from nucleus of Comet Halley. Birkeland emulated jets from a cathode in a vacuum tube (see below) Source/credit
Comets: Kristian Birkeland's theory
![Heliospheric current sheet](https://www.plasma-universe.com/wp-content/uploads/Heliospheric-current-sheet_edit-300x210.jpg)
The heliospheric current sheet results from the influence of the Sun's rotating magnetic field on the plasma in the interplanetary medium [1]
Current sheet
![Saturn Aurora](https://www.plasma-universe.com/wp-content/uploads/Saturn-aurora-300x253.jpg)
Saturnian aurora whose reddish colour is characteristic of ionized hydrogen plasma.[1] Powered by the Saturnian equivalent of (filamentary) Birkeland currents, streams of charged particles from the interplanetary medium interact with the planet's magnetic field and funnel down to the poles.[2] Double layers are associated with (filamentary) currents,[3][4] and their electric fields accelerate ions and electrons.[5]
Double layer
![Heliospheric current sheet](https://www.plasma-universe.com/wp-content/uploads/Heliospheric-current-sheet_edit-300x210.jpg)
The Heliospheric current sheet carries a total electric current of about three trillion Amps (3×109 Amps)[1] Source
Electric currents in space plasmas
![Sun Corona](https://www.plasma-universe.com/wp-content/uploads/Sun-corona-300x266.jpg)
The Sun's immense gravity is unable to hold onto the "solar wind" which streams away at about 400km per second Source
Electromagnetic force
![Plasma Lamp](https://www.plasma-universe.com/wp-content/uploads/Plasma-lamp_2-296x300.jpg)
A plasma lamp, illustrating some of the more complex phenomena of a plasma, including filamentation. Source/credit
Plasma
![Aurora Earth](https://www.plasma-universe.com/wp-content/uploads/Aurora-earth-300x267.jpg)
Planet Earth showing four states of matter, (1) the plasma aurora, (2) the gaseous atmosphere, (3) the liquid oceans, and (4) the solid Arctic ice. Source
Plasma: the first state of matter
![Willard Harrison Bennett](https://www.plasma-universe.com/wp-content/uploads/Willard-harrison-bennett-300x270.jpg)
Willard Harrison Bennett (far right) with colleagues at the U.S. Naval Research Laboratory, working on the Störmertron tube Source
Willard Harrison Bennett
![](https://www.plasma-universe.com/wp-content/uploads/Wolf-effect-doppler-like-graph-300x229.png)
Wolf Effect illustrated. The chart shows idealized spectral lines of ionized oxygen (black lines, right) at rest, together with Doppler-shifted lines (red) due to motion of the source, and Wolf-shifted lines (blue) at rest. Note that three free parameters are arbitrarily chosen by the authors to obtain a shape that mimics the Doppler shift as closely as possible. The authors report observing a decrease in frequency for a Wolf Effect, but do not report observing as precise a correspondence as this since the detail conditions for the Wolf Effect to mimic a Doppler redshift are difficult to come by. [1] Source