this post was submitted on 06 Feb 2024
638 points (96.2% liked)

News

23310 readers
3675 users here now

Welcome to the News community!

Rules:

1. Be civil


Attack the argument, not the person. No racism/sexism/bigotry. Good faith argumentation only. This includes accusing another user of being a bot or paid actor. Trolling is uncivil and is grounds for removal and/or a community ban. Do not respond to rule-breaking content; report it and move on.


2. All posts should contain a source (url) that is as reliable and unbiased as possible and must only contain one link.


Obvious right or left wing sources will be removed at the mods discretion. We have an actively updated blocklist, which you can see here: https://lemmy.world/post/2246130 if you feel like any website is missing, contact the mods. Supporting links can be added in comments or posted seperately but not to the post body.


3. No bots, spam or self-promotion.


Only approved bots, which follow the guidelines for bots set by the instance, are allowed.


4. Post titles should be the same as the article used as source.


Posts which titles don’t match the source won’t be removed, but the autoMod will notify you, and if your title misrepresents the original article, the post will be deleted. If the site changed their headline, the bot might still contact you, just ignore it, we won’t delete your post.


5. Only recent news is allowed.


Posts must be news from the most recent 30 days.


6. All posts must be news articles.


No opinion pieces, Listicles, editorials or celebrity gossip is allowed. All posts will be judged on a case-by-case basis.


7. No duplicate posts.


If a source you used was already posted by someone else, the autoMod will leave a message. Please remove your post if the autoMod is correct. If the post that matches your post is very old, we refer you to rule 5.


8. Misinformation is prohibited.


Misinformation / propaganda is strictly prohibited. Any comment or post containing or linking to misinformation will be removed. If you feel that your post has been removed in error, credible sources must be provided.


9. No link shorteners.


The auto mod will contact you if a link shortener is detected, please delete your post if they are right.


10. Don't copy entire article in your post body


For copyright reasons, you are not allowed to copy an entire article into your post body. This is an instance wide rule, that is strictly enforced in this community.

founded 1 year ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
[–] Feathercrown@lemmy.world 1 points 9 months ago (2 children)

That's worded strangely (powering the lasers takes both 300 and 2.05 megajoules?) but oof

[–] alkheemist@aussie.zone 4 points 9 months ago

Powering the laser takes 300 MJ but the actual laser power (the energy in the light) is only 2.05 MJ. The rest of the energy is lost to heat and other inefficiencies. If the laser could be created with 100% efficiency then the input energy would also be 2.05 MJ.

[–] Resonosity@lemmy.world 3 points 9 months ago* (last edited 9 months ago)

Energy can be measured as occurring in different physical phenomena. There is energy in sound waves/packets, energy in light waves/packets, energy in matter, etc.

The 300 MJ number refers to the electrical energy in the form of electromagnetic fields carried specifically through solid conductors via electron movement along the conductors.

The 2.05 MJ number refers to the radiative energy in the form of electromagnetic fields sent specifically through free space/a vacuum (I presume; I didn't read the article, so maybe the laser medium was a vacuum or something else) via photons/waves. No electrons, aside from those in the lasers that create the photons in the first place.

So there is a conversion from electric to radiative energy here.

Start Edit:

And as another commenter said, in this conversion there are losses because materials aren't perfect.

:End Edit

If the 3 MJ radiant energy from the nuclear material was then converted back into electric energy via steam processes, we'd get a comparable number compared to the 300 one.

This is also why you see nuclear/CSP plants quoted in MWt and MWe: there is a conversion that takes place from thermal energy (vibrations of atoms/compounds) into electric energy.