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Intense laser experiments provide evidence that light can stop electrons

www3.imperial.ac.uk

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Re: Intense laser experiments provide evidence that light can stop electrons

#3
What on earth, light by definition is the quantifiable (quanta) of energy levels between electron orbital states. This is such a nonsensical title, as the electron would be changing electron states based off the energy level of the laser - of course! Any suggestions on what the title should be changed to?

Re: Intense laser experiments provide evidence that light can stop electrons

#4

What on earth, light by definition is the quantifiable (quanta) of energy levels between electron orbital states. This is such a nonsensical title, as the electron would be changing electron states based off the energy level of the laser - of course! Any suggestions on what the title should be changed to?

Is that what this article is about? I read this article as being about a quantum phenomenon where the photon beam absorbed the momentum from an electron beam in a manner quite different from how they would interact at lower intensities.

Re: Intense laser experiments provide evidence that light can stop electrons

#5

What on earth, light by definition is the quantifiable (quanta) of energy levels between electron orbital states. This is such a nonsensical title, as the electron would be changing electron states based off the energy level of the laser - of course! Any suggestions on what the title should be changed to?

Ok, not even even about electrons in orbit. First couple paragraphs mention an electron beam.

Re: Intense laser experiments provide evidence that light can stop electrons

#6
Study: Experimental Evidence of Radiation Reaction in the Collision of a High-Intensity Laser Pulse with a Laser-Wakefield Accelerated Electron Beam

Citation: J. M. Cole, K. T. Behm, E. Gerstmayr, T. G. Blackburn, J. C. Wood, C. D. Baird, M. J. Duff, C. Harvey, A. Ilderton, A. S. Joglekar, K. Krushelnick, S. Kuschel, M. Marklund, P. McKenna, C. D. Murphy, K. Poder, C. P. Ridgers, G. M. Samarin, G. Sarri, D. R. Symes, A. G. R. Thomas, J. Warwick, M. Zepf, Z. Najmudin, and S. P. D. Mangles. Phys. Rev. X 8, 011020 – 2018-02-07

Link: https://doi.org/10.1103/PhysRevX.8.011020

DOI: 10.1103/PhysRevX.8.011020

Abstract: The dynamics of energetic particles in strong electromagnetic fields can be heavily influenced by the energy loss arising from the emission of radiation during acceleration, known as radiation reaction. When interacting with a high-energy electron beam, today’s lasers are sufficiently intense to explore the transition between the classical and quantum radiation reaction regimes. We present evidence of radiation reaction in the collision of an ultrarelativistic electron beam generated by laser-wakefield acceleration (ε > 500 MeV) with an intense laser pulse (a0 > 10). We measure an energy loss in the postcollision electron spectrum that is correlated with the detected signal of hard photons (γ rays), consistent with a quantum description of radiation reaction. The generated γ rays have the highest energies yet reported from an all-optical inverse Compton scattering scheme, with critical energy εcrit > 30 MeV.

Re: Intense laser experiments provide evidence that light can stop electrons

#9

What on earth, light by definition is the quantifiable (quanta) of energy levels between electron orbital states. This is such a nonsensical title, as the electron would be changing electron states based off the energy level of the laser - of course! Any suggestions on what the title should be changed to?

Reading the article might help.

Re: Intense laser experiments provide evidence that light can stop electrons

#10
The HN title is incorrect -- perhaps the first direct evidence is Compton's original work, showing that electrons scatter photons. If electrons scatter photons, then photons scatter electrons.

Every time a photon scatters off an electron, there exists a reference frame in which the electron is brought to rest.

I'm certain that one could find an earlier argument than Compton scattering, too. Maxwell surely would have agreed that light could exert force upon charges.

The experiment to which the HN title links, however, is awesome, and is perhaps the first time one has demonstrated stopping 0.5 GeV electrons in a wall of light.

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