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Full-Text Articles in Physics
Detailed Dynamics Of Electron Beams Self-Trapped And Accelerated In A Self-Modulated Laser Wakefield, Shouyuan Chen, M. Krishnan, Anatoly Maksimchuk, R. Wagner, Donald P. Umstadter
Detailed Dynamics Of Electron Beams Self-Trapped And Accelerated In A Self-Modulated Laser Wakefield, Shouyuan Chen, M. Krishnan, Anatoly Maksimchuk, R. Wagner, Donald P. Umstadter
Donald Umstadter Publications
The electron beam generated in a self-modulated laser-wakefield accelerator is characterized in detail. A transverse normalized emittance of 0.06 π mm mrad, the lowest ever for an electron injector, was measured for 2 MeV electrons. The electron beam was observed to have a multicomponent beam profile and energy distribution. The latter also undergoes discrete transitions as the laser power or plasma density is varied. In addition, dark spots that form regular modes were observed in the electron beam profile. These features are explained by analysis and test particle simulations of electron dynamics during acceleration in a three-dimensional plasma wakefield.
Electron Injection By Dephasing Electrons With Laser Fields, E. Dodd, J.K. Kim, Donald P. Umstadter
Electron Injection By Dephasing Electrons With Laser Fields, E. Dodd, J.K. Kim, Donald P. Umstadter
Donald Umstadter Publications
The authors seek to review injection concepts for plasma based acceleration. It is shown that regardless of injection mechanism, resultant beams will be similar due to wave structure. Also, most schemes employ the same basic processes, namely the dephasing of electrons by laser fields, and can thus be analyzed with similar approaches.
Acceleration Of Electrons In A Self-Modulated Laser Wakefield, Shouyuan Chen, M. Krishnan, Anatoly Maksimchuk, Donald P. Umstadter
Acceleration Of Electrons In A Self-Modulated Laser Wakefield, Shouyuan Chen, M. Krishnan, Anatoly Maksimchuk, Donald P. Umstadter
Donald Umstadter Publications
Acceleration of electrons in a self-modulated laser-wakefield is investigated. The generated electron beam is oberved to have a multi-component beam profile and its energy distribution undergoes discrete transitions as the conditions are varied. These features can be explained by simple simulations of electron propagation in a 3-D plasma wave.
Laser Light In, 50-Mev Protons Out, Phillip F. Schewe, Ben Stein, Donald P. Umstadter
Laser Light In, 50-Mev Protons Out, Phillip F. Schewe, Ben Stein, Donald P. Umstadter
Donald Umstadter Publications
At next week's meeting of the American Physical Society Division of Plasma Physics in Seattle, three groups will independently announce their ability to generate powerful, intense streams of ions by shining ultrashort laser pulses on tiny spots of solid material. Potentially, this approach offers an alternative to bulky, expensive ion accelerators for producing high-velocity ions useful for cancer therapy and electronics manufacturing. Using a single pulse of light from Livermore's Petawatt laser, the most powerful in the world, researchers at that laboratory (Scott Wilks, 925-422-2974, wilks@icf.llnl.gov) have reported generating 30 trillion protons with energies up to 50 MeV, from a …
Self-Focusing, Channel Formation, And High-Energy Ion Generation In Interaction Of An Intense Short Laser Pulse With A He Jet, G.S. Sarkisov, B. Yu. Bychenkov, V.N. Novikov, V.T. Tikhonchuk, Anatoly Maksimchuk, Shouyuan Chen, R. Wagner, G. Mourou, Donald Umstadter
Self-Focusing, Channel Formation, And High-Energy Ion Generation In Interaction Of An Intense Short Laser Pulse With A He Jet, G.S. Sarkisov, B. Yu. Bychenkov, V.N. Novikov, V.T. Tikhonchuk, Anatoly Maksimchuk, Shouyuan Chen, R. Wagner, G. Mourou, Donald Umstadter
Donald Umstadter Publications
Using interferometry, we investigate the dynamics of interaction of a relativistically intense 4-TW, 400-fs laser pulse with a He gas jet. We observe a stable plasma channel 1 mm long and less than 30 μm in diameter, with a radial gradient of electron density ∼5×1022 cm-4 and with an on-axis electron density approximately ten times less than its maximum value of 8×1019 cm-3. A high radial velocity of the surrounding gas ionization of ∼3.8×108 cm/s has been observed after the channel formation, and it is attributed to the fast ions expelled from the laser …