tgray

One last plasma note for the day: the term was coined by Irving Langmuir. Read his wiki page and feel inadequate. Coincidentally, he was the inspiration for the scientist in Vonnegut’s Cat’s Cradle. I recommend The Brothers Vonnegut for those interested. 🔬🔭🚀🛰📖

tgray

So plasmas. Where do they occur?

  • Fluorescent & neon bulbs
  • Stars
  • Plasma processing
  • Fusion reactors
  • Ion engines and other electric propulsion devices
  • Arc welders (and electric arcs)
  • Plasma TVs
  • Auroras
  • Lightning (and static electricity)
  • HID bulbs

🔬🔭🚀🛰

tgray

Hot plasmas are really hot.

  • core of sun: 1.2 keV -> 15 million ˚C
  • (big) fusion reactors: 10’s of keV

🔬🔭🚀🛰

tgray

Since plasmas are ionized, they (typically) have a lot of energy, i.e. ‘hot.’ Even low temperature (classical) plasmas are hot. Electrons in those have temperatures of 1-10 eV (electron volts). What’s an eV? 11600 Kelvin. So a ‘cold’ 1 eV plasma is 11,300 Celsius. 🔬🔭

tgray

Plasmas exhibit what is called collective behavior (think waves). They also react to electric and magnetic fields, as well as support carrying currents in them (like a conductor/wire). We will use these behaviors later.🔬🔭

tgray

A few common questions about plasma, with short answers:

  • “Is it the same as blood plasma?” No.
  • “Is it the same as plasma TVs?” Yes.
  • “Explain how a plasma globe works.” That’s complicated. So no. :)

🔬🔭

tgray

One ionization event does not make a plasma. We need a bunch. When you get a bunch, you have a quasi-neutral soup of positive (ions) and negative (electrons) charges. There are other types of plasmas (quark-gluon, non-neutral, dusty), but this is the classical one. 🔬🔭🚀🛰

tgray

As I mentioned yesterday, I’m a plasma physicist. What is a plasma? When you pump enough energy into matter, the electrons can escape from the neutral atoms. This is called ionization. The byproducts are an ion (positively charged nucleus of atom) and an electron.🔬🔭🚀🛰

tgray

I know there is one other plasma guy on micro.blog, @dcpace, so I’m going to tag him right now. He is still active in the fusion field and works at one of the most advanced tokamaks in the world, DIII-D. 🔬🔭

tgray

First, a little about myself. I am a plasma physicist. I started off studying nuclear fusion, then worked on some ‘basic plasma physics’ topics for a few years. I took a brief detour while I worked as a valve designer before I ended up working on electric propulsion. 🔬🔭🚀🛰

tgray

I’m purposefully breaking it up across many days; I don’t want it to be a giant sprawling blog post that no one will ever read. I’ll try to do a few meaningful bits every day, but no promises. 🔬🔭🚀🛰

tgray

I have a little free time on my hands right now, so I thought it would be a good idea to flesh out the science and space topics here. This will be a meandering discussion. Please feel free to stop me and ask questions. Or to redirect the conversation.🔬🔭🚀🛰

tgray

@burk Are any of the science tagmojis active? I’m planning on writing some posts with some science content and want to tag it right… 🔭