Soft-X-ray harmonic comb from relativistic electron spikes

A. S. Pirozhkov, M. Kando, T. Zh Esirkepov, P. Gallegos, H. Ahmed, E. N. Ragozin, A. Ya Faenov, T. A. Pikuz, T. Kawachi, A. Sagisaka, J. K. Koga, M. Coury, J. Green, P. Foster, C. Brenner, B. Dromey, D. R. Symes, M. Mori, K. Kawase, T. KameshimaY. Fukuda, L. Chen, I. Daito, K. Ogura, Y. Hayashi, H. Kotaki, H. Kiriyama, H. Okada, N. Nishimori, T. Imazono, K. Kondo, T. Kimura, T. Tajima, H. Daido, P. Rajeev, P. McKenna, M. Borghesi, D. Neely, Y. Kato, S. V. Bulanov

Research output: Contribution to journalArticlepeer-review

68 Citations (Scopus)


We demonstrate a new high-order harmonic generation mechanism reaching the "water window" spectral region in experiments with multiterawatt femtosecond lasers irradiating gas jets. A few hundred harmonic orders are resolved, giving μJ/sr pulses. Harmonics are collectively emitted by an oscillating electron spike formed at the joint of the boundaries of a cavity and bow wave created by a relativistically self-focusing laser in underdense plasma. The spike sharpness and stability are explained by catastrophe theory. The mechanism is corroborated by particle-in-cell simulations.

Original languageEnglish
Article number135004
JournalPhysical review letters
Issue number13
Publication statusPublished - 2012 Mar 30
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)


Dive into the research topics of 'Soft-X-ray harmonic comb from relativistic electron spikes'. Together they form a unique fingerprint.

Cite this