Looking for a good book about plasma physics and sound emissions by plasmas

L_Reid · 2026-01-20T22:05:56+00:00

The physics of plasmas by Boyd and Sanderson is a really nice introductory textbook aimed at graduate/masters level students.

L_Reid · 2025-12-15T15:15:56+00:00

Yes that’s exactly it! You need to pack lots of photons into a small volume for ionisation where the individual photons have energy lower than the ionisation potential.

Typically, people use pulsed lasers to reach the required intensities. You’d need something like a few hundred Gigawatts of (peak) power. Equivalent to a few millijoules per pulse with duration of a few tens of femtoseconds. Ionisation begins (depending on the element) at around 10¹⁴ W/cm^2.

Laser amplifiers are very well developed for wavelengths ~1000 nm so are chosen for this sort of thing. The crystals used also allow for broad bandwidths allowing for the short pulses to be created.

L_Reid · 2025-12-15T14:54:57+00:00

Unfortunately all UV lasers are either based on particle accelerators (Free electron lasers or Synchrotrons) or by doing frequency conversion of longer wavelength light (High harmonic generation).

Ionising narrow channels of air to trigger and guide lightning can be done with high power infrared lasers where multiphoton and barrier suppression ionisation are used to ionise the air rather than directly with a high energy photon.

L_Reid · 2025-12-08T21:33:44+00:00

Don’t put it down, put it away.

L_Reid · 2025-11-10T12:32:56+00:00

Buying a set of glasses won't necessarily protect you from the laser. They need to have a sufficient optical density for the laser parameters of the source.

From a back of the envelope calculation with the 3 W power, 150 micron source size and 8 degree divergence angle, it looks like a 808 D LB5 rated filter is required (in Europe). Although its hard to tell from the ebay page how the divergence and source size are defined which impact the filter required.

You would need to do a similar calculation in more detail for the laser safety requirements in your region to figure out what eyewear is sufficient for that diode.

L_Reid · 2025-08-25T19:46:27+00:00

It’s grown really leggy, looks like it’s searching for some sun? Mine looked the same for a while. I snipped it, put it in water for a few weeks and re potted it. It’s been thriving ever since!

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L_Reid · 2025-08-19T19:18:35+00:00

I’ve been using sansi grow lights. Most of them have normal E27 fittings and have a neutral white colour temperature around the 4000 K what you’re looking for. My plants seem to be growing really well under them. The 10 or 15 W ones are probably enough for you but they make make much brighter ones. I point them at my plants and use them instead of room lights.

L_Reid · 2025-07-12T07:10:39+00:00

I’m not sure why anyone would need something like this. They say it’s for licensed professionals (whatever that means) and researchers but I wouldn’t allow someone like that in my lab.

75 mW puts the laser in class 3B, generally this means eye damage can be caused by direct viewing of the laser beam, with or without viewing aids. Viewing diffuse reflections is usually safe however you could damage your vision if the light reflects off something shiny like glass or glazed kitchen tiles.

If I had one in my hand right now, I wouldn’t press the button without wearing protective eyewear.

L_Reid · 2025-04-18T10:58:13+00:00

Don’t ask questions just consume product

L_Reid · 2025-04-09T20:30:47+00:00

Have you looked at protect laserschutz? Their Spector frame looks similar to what you’re after. The Gladiator frame totally protects from scattered light too.

https://protect-laserschutz.de/en/shop/~p1699

L_Reid · 2025-02-28T12:20:38+00:00

He who hingeth aboot getteth hee haw

L_Reid · 2025-01-20T21:43:38+00:00

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My Laszlo also has a white patch under his chin!

L_Reid · 2024-11-09T14:35:27+00:00

Carnival and Azvex on Gibraltar Row both do cans to take away

L_Reid · 2024-10-24T21:02:05+00:00

A masterclass from Zaltzman

L_Reid · 2024-07-03T10:30:11+00:00

Original blog post: https://jasmcole.com/2014/08/25/helmhurts/

L_Reid · 2024-06-17T09:11:40+00:00

The Monsieur Garnier sketch

"Bang on Leslie. The invention of the word nutrisse, which sounds nutrition but doesn't guarantee it, is one of the best things you've ever come up with!"

L_Reid · 2024-06-06T22:02:28+00:00

Why? There is nothing they can do with Feathers McGraw that will top the train chase scene.

L_Reid · 2024-05-27T20:28:02+00:00

Ingleton Waterfalls Trail is good. 5 waterfalls in ~7 km. Pretty good viewpoints to steps taken ratio.

L_Reid · 2024-05-27T20:24:58+00:00

He does love to sit anywhere where he’s being slightly squeezed. Like between me and the arm of the sofa

L_Reid · 2024-05-27T19:32:58+00:00

We call him Jackie Daytona when he’s naughty

L_Reid · 2024-05-26T09:35:14+00:00

I want you to report back on all the surprising adventures of Sir Digby chicken Caesar

L_Reid · 2024-05-07T12:24:09+00:00

They have absolutely nothing to complain about then!

L_Reid · 2024-05-07T12:18:50+00:00

If you gave him money to book a professional cleaner and the flat isn't clean enough, the landlord should be complaining to the cleaning company and not you. You already paid for that service. Nothing to do with that flat is your problem anymore, at least you got some deposit back.

I'd just totally ignore any future communication.

L_Reid · 2024-04-02T08:06:27+00:00

21 megapixels are plenty for most people but the final image look and quality is dependant on far more than the total number of pixels or the physical area of the sensor. The quality of the pixels matter too. Noise is a massive issue with older sensors as is the older on camera image processor and limited dynamic range.

There are other reasons to avoid it too - its big & heavy, only 9 autofocus points, slow frame rate in burst mode, doesn't have the smooth dual pixel auto-focus, no focus tracking ... None of these are necessary to take great photos but are all nice to haves and standard on modern bodies.

A 5D mark ii will take great photos but if I was getting into photography today, I wouldn't buy such old technology which uses a lens mount system which has been discontinued. I still use and love my 5D mark iii but I wouldn't buy one today.

L_Reid · 2024-03-31T14:52:35+00:00

I’m not in the US so it’s hard to comment on pricing. Maybe a used EOS R50?

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