Investigating Super Efficient Laser Propulsion Leads to Serendipitous UV effects

wvanhuffel writes "In this article from spacedaily the authors may be on the road to creating the impulse engine....then again, maybe not. It's life imitating art again!" The article details the exploration of the use of lasers and more importantly a new effect when certain materials (in this case lead) are struck by the laser, apparantly a predictable secondary explosion 50 millionths of a second after the target is struck, emitting UV light.

Comments

Lasering electrons off the particles.

[Nyphur]

Here's a little theory I thought up there now, while reading the full article on spacedaily:
Remember, I'm only 16 so I don't have enough grounding in particle physics to make a more solid theory.

The particles are ionised because the laser (a highly coherent beam of focused photons) interacts with the electrons in the lead atoms. The photons literally knock the electrons in the atoms of the lead further back into the lead by giving them energy and raising the resistance back towards the laser.

A lot of energy is, at the same time, given to lots of particles of lead. The particles of lead given energy are those in the direct path of the laser and thus are those which have had their electrons removed by the laser, thus producing the ionised lead cloud.

With all this energy stored up in the electrons, which have no atoms to return to, it has to go somewhere! The electrons cannot enter the outer electron shells of the lead atoms, so they are bounced around the lead, attracted by the gravitational pull of the atoms but repelled by the electrons, while possibly forcing electrons with less energy than them out of the outer electron shells and replacing them.

When an electron is forced out of its shell (as in the first case 1millionth of a second after the laser discontinues) it emits the energy it had stored in the bond, like splitting the bonds in an actual atom, but with less intensity. When the electrons are forced out in the second case (50 millionths of a second after the first wave), energy is used in making the new bonds and the same ammount is used in breaking the old bonds, BUT the electrons making the new bond and breaking the old ones already have a lot of energy from the laser, which is released when the electrons enter the outer electron shells of the atoms, because the energy released from breaking the bonds cannot enter the energy-saturated electrons and the energy taken in from making the bond is already present in the electrons entering the shell.

I bet it's a mechanical effect

[ka9dgx]

I bet the laser creates an acoustic shock wave is transversing the lead, reflecting back, and hittle the already excited atoms again, 50 microseconds later.

They should try thicker/thinner films.

--Mike--

Impulse Engine it's not

[Rick the Red]

This is a reaction engine. Lead may be the reactant, and lasers may be the energy source, but the propulsion is still caused by tossing mass away from the direction you wish to move.

A true impulse engine does not lose mass, just energy, and is still a fiction. That's not what these folks are working on.

Re:Impulse Engine it's not

[geekoid]

I thought it was called an "impulse engine" because it would be used as a plot device when ever the director had the impulse to use it...