New Accelerator Technique Doubles Particle Energy 124
ZonkerWilliam writes "Plasma wake particle accelerators are making surprisingly quick advances. It was a just a little while ago we had GeV acceleration in 3cm. Now they are capable of doubling the energy of electrons. 'Imagine a car that accelerates from zero to sixty in 250 feet, and then rockets to 120 miles per hour in just one more inch. That's essentially what a collaboration of accelerator physicists has accomplished, using electrons for their race cars and plasma for the afterburners. Because electrons already travel at near light's speed in an accelerator, the physicists actually doubled the energy of the electrons, not their speed.'"
Re:E=1/2 m v^2 (Score:5, Insightful)
Re:Misunderstanding (Score:3, Insightful)
Re:Don't we all love comparisons for laymen (Score:3, Insightful)
A simile depends on having a kind of mapping between one domain and another. These allow you to use reasoning from one domain to reason in another. That's why they're so useful - by using such a mapping, people inexperienced in one domain can still reason in it by leveraging their experience in another. For example, when Shakespeare says "Shall I compare thee to a summer's day" he points out that some of our reasoning about summer's days can be applied to people too. For example, just as many people are disappointed when we know there will be no more summer's days as autumn approaches, we know that Shakespeare would be disappointed if separated from the subject of his sonnet for an extended period of time. We know this even though he doesn't say it explicitly because he has set up a mapping that allows us to reason about his subject.
Sometimes the mapping is a direct translation. For example if someone says that detecting a pulsar with a new radio telescope is like seeing a candle on the moon we can guess that maybe the power being received from the pulsar is the same as the power received from a candle on the moon. Sometimes it's a scaling. For example if someone says that a flea's jump is like a human jumping over the Empire State building we guess that if we were to scale a human down to the size of a flea, then applying the same scaling to the said building would reduce it to the height of a flea's jump.
So now I can say what my complaint about this simile is. It gives no idea what the mapping is. Actually, it's worse, I can partly see what the mapping is, but the concepts I use to do this aren't in the grasp of the very people it is designed to help. But even in this case it's only a partial understanding. I don't know if the energy of the car is meant to be literally the same energy as that of the particle. I don't know if the 250ft is meant to be taken literally. And the stupid thing is that ordinary people have no intuition about the energy stored in a non-relativistic moving object, let alone a relativistic one. So most people are probably inclined to try to set up an interpretation of the mapping in terms of the car's velocity - and that's the wrong mapping.
The example is stupid... (Score:3, Insightful)
Re:Only for small values of v (Score:3, Insightful)
Re:Misunderstanding (Score:3, Insightful)
Re:Cue people who pretend they understand the scie (Score:5, Insightful)
Cue people who pretend they understand the science...
As mentioned, there are some of us around here who are actual scientists. However, there are no details in the article, thus no science to understand. All I found were crappy analogies with afterburners and some hand-wavey crap about plasma. I'm pretty sure that if it were as easy as running some crap through a plasma to accelerate it, it would have been done some time ago. And there are a number of pertinent questions:
Why do they have to use a 2-mile accelerator if the plasma can do in a foot what it takes the 2 miles to do?
Why can't it be longer?
How is the plasma chamber set up? I'm guessing it's probably an coupled with an RF field, which can accelerate a plasma, but details, come on!