Subscribe free to our newsletters via your
. 24/7 Space News .




TECH SPACE
Physicists demonstrate the acceleration of electrons by a laser in a vacuum
by Staff Writers
Los Angeles CA (SPX) Mar 05, 2013


File image.

Accelerating a free electron with a laser has been a longtime goal of solid-state physicists. David Cline, a distinguished professor in the UCLA Department of Physics and Astronomy, and Xiaoping Ding, an assistant researcher at UCLA, have conducted research at Brookhaven National Laboratory in New York and have established that an electron beam can be accelerated by a laser in free space.

This has never been done before at high energies and represents a significant breakthrough, Cline said, adding that it also may have implications for fusion as a new energy source.

In free space, a plane-wave laser is unable to accelerate an electron, according to the Lawson-Woodward theorem, posited in 1979. However, Yu-kun Ho, a professor at China's Fudan University in Shanghai, and his research group have proposed a concept of what physicists refer to as the capture-acceleration scenario to show that an electron can be accelerated by a tightly focused laser in a vacuum.

In the capture-acceleration scenario, the diffraction from a tightly focused laser changes not only the intensity distribution of the laser but also its phase distribution, which results in the field phase velocity being lower than the speed of light in a vacuum in some areas.

Thus, a channel that overlaps features of both strong longitudinal electric field and low-laser-phase velocity is created, and electrons can receive energy gain from the laser. The acceleration effect increases along with increasing laser intensity, Cline said. This channel for electrons may be useful for other scientific endeavors, such as guiding an electron beam into a specific region of laser fusion applications, he said.

A possible application of this discovery is the use of laser plasma fusion to provide a new energy source for the U.S. and other countries. The focus of the laser generates a natural channel that can capture electrons and drive them into a pellet that explodes, by fusion, to produce excess energy, Cline said.

With federal funding from the U.S. Department of Energy, a project to carry out a proof-of-principle beam test for the novel vacuum acceleration at Brookhaven National Laboratory's Accelerator Test Facility (BNL-ATF) has been proposed and approved - a collaboration among the UCLA Center for Advanced Accelerators, of which Cline is principal investigator, Ho's group and the Accelerator Test Facility team.

BNL-ATF is one of the few facilities that can provide both a high-quality electron beam and a high-intensity laser beam for the beam test, Cline said. Ho's group provides theoretical support. UCLA scientists - Cline, Ding and Lei Shao, a former UCLA physics graduate student of Cline's - are responsible for the whole experiment and the experimental data analysis.

Simulation research work and hardware design have been done in accordance with BNL-ATF's experimental conditions. The simulation results predict that vacuum laser acceleration phenomena can be observed with ATF's diagnostic system.

Cline, Ding, Ho and their colleagues published two papers last month on this research: "Simulation Prediction and Experiment Setup of Vacuum Laser Acceleration at Brookhaven National Lab-Accelerator Test Facility," in the journal Nuclear Instruments and Methods in Physics Research A, and the discovery paper "First Observation of Acceleration of Electrons by a Laser in a Vacuum," in the Journal of Modern Physics.

The major result of the experiment is to show the increase of beam energy caused by the laser, as illustrated in the attached graph of data collected from the spectrometer on beam line No. 1 at BNL-ATF.

Each row of two frames represents one snapshot-pair of "laser on" (right side) and "laser off" (left side) with unchanged configuration. One can see a clear increase from these pictures, proof that the laser accelerates the 20 mega-electron-volts electron beam in vacuum.

The length of the beam image reveals the energy spread of the beam. The experiment recorded 30 shots. Twenty shots were high-intensity and showed effects of the laser on/laser off difference. Four shot examples are shown in the graph.

UCLA 'Higgs factory' workshop: March 21

The UCLA Department of Physics and Astronomy will sponsor a workshop from March 21 to 23 on the Higgs boson and the development of a Higgs factory muon collider. Topics at the workshop will include the latest results from the Large Hadron Collider and the importance of the Higgs boson particle. For more information, visit http://ucla.in/V85UyL.

"The discovery of the Higgs boson last July 4 is one of the greatest discoveries of all time and a key to understanding the universe," Cline said.

"However, in order to study this in detail, a new source must be built to produce hundreds of thousands of Higgs particles per year and to study the detailed properties that could tell us more about the origin of this particle and other new physics.

"This UCLA workshop will discuss 'Higgs factories.' We expect experts in accelerator physics, cosmology and particle physics to attend. With interest building after the discovery of a particle consistent with the Higgs boson, doors are opening to a new range of questions and discussions."

.


Related Links
University of California - Los Angeles
Space Technology News - Applications and Research






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle








TECH SPACE
Looking out for lasers
Paris (ESA) Feb 11, 2013
ESA's laboratories are equipped with a huge range of measuring tools, but the most versatile remains the human eye - and it must be looked after. These protective goggles are worn while using lasers to align plasma-measuring probes, in preparation for test firings of space thrusters in ESA's Propulsion Laboratory. Based at ESA's technical centre ESTEC in Noordwijk, the Netherlands, t ... read more


TECH SPACE
China to use modified rocket for moon landing mission

Water On The Moon: It's Been There All Along

Building a lunar base with 3D printing

US, Europe team up for moon fly-by

TECH SPACE
Short Bump Gets Robotic Arm Closer to Rock Target

NASA fixing computer glitch on Mars Curiosity rover

Inspiration Mars to Pursue Human Mission to the Red Planet in 2018

Computer Swap on Curiosity Rover

TECH SPACE
Tech sector rides on rich list

Brazil inventor struggles to collect royalties

Stanford scientist closes in on a mystery that impedes space exploration

U.S. research to be free online

TECH SPACE
China to launch new manned spacecraft

Woman expected again to join next China crew roster

China's space station will be energy-efficient

China plans manned space mission

TECH SPACE
ESA's Columbus Biolab Facility

SpaceX set for third mission to space station

Record Number of Students Control ISS Camera

NASA briefly loses contact with space station

TECH SPACE
SpaceX's capsule arrives at ISS

Dragon Transporting Two ISS Experiments For AMES

SpaceX Optimistic Despite Dragon Capsule Mishap

'Faulty Ukrainian Parts' Blamed for Zenit Launch Failure

TECH SPACE
Scientists spot birth of giant planet

NASA's Kepler Mission Discovers Tiny Planet System

Kepler helps astronomers find tiny exo planet

Searching for a Pale Blue SPHERE in the Universe

TECH SPACE
Creating your own animated 3D characters and scenes for the web

Towards more sustainable construction

Physicists demonstrate the acceleration of electrons by a laser in a vacuum

SimCity rebuilt for modern life




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement