Comment on

• Energy doubling of 42 GeV electrons in a metre-scale plasma wakefield accelerator.

  Blumenfeld I, Clayton CE, Decker FJ, Hogan MJ, Huang C, Ischebeck R, Iverson R, Joshi C, Katsouleas T, Kirby N, Lu W, Marsh KA, Mori WB, Muggli P, Oz E, Siemann RH, Walz D, Zhou M. Blumenfeld I, et al. Nature. 2007 Feb 15;445(7129):741-4. doi: 10.1038/nature05538. Nature. 2007. PMID: 17301787