Antiproton cloud compression in the ALPHA apparatus at CERN

A. Gutierrez, M. D. Ashkezari, M. Baquero-Ruiz, W. Bertsche, C. Burrows, E. Butler, A. Capra, C. L. Cesar, M. Charlton, R. Dunlop, S. Eriksson, N. Evetts, J. Fajans, T. Friesen, M. C. Fujiwara, D. R. Gill, J. S. Hangst, W. N. Hardy, M. E. Hayden, C. A. IsaacS. Jonsell, L. Kurchaninov, A. Little, N. Madsen, J. T. K. McKenna, S. Menary, S. C. Napoli, P. Nolan, K. Olchanski, A. Olin, P. Pusa, C. Rasmussen, F. Robicheaux, R. L. Sacramento, E. Sarid, D. M. Silveira, C. So, S. Stracka, J. Tarlton, T. D. Tharp, R. I. Thompson, P. Tooley, M. Turner, D. P. van der Werf, J. S. Wurtele, A. I. Zhmoginov

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


We have observed a new mechanism for compression of a non-neutral plasma, where antiprotons embedded in an electron plasma are compressed by a rotating wall drive at a frequency close to the sum of the axial bounce and rotation frequencies. The radius of the antiproton cloud is reduced by up to a factor of 20 and the smallest radius measured is ∼ 0.2 mm. When the rotating wall drive is applied to either a pure electron or pure antiproton plasma, no compression is observed in the frequency range of interest. The frequency range over which compression is evident is compared to the sum of the antiproton bounce frequency and the system’s rotation frequency. It is suggested that bounce resonant transport is a likely explanation for the compression of antiproton clouds in this regime.

Original languageEnglish
Pages (from-to)21-28
Number of pages8
JournalHyperfine Interactions
Issue number1-3
StatePublished - 1 Nov 2015
Externally publishedYes


  • Antihydrogen
  • Antiprotons
  • Compression
  • Electrons
  • Non-neutral plasma
  • Penning-Malmberg trap
  • Rotating wall

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Nuclear and High Energy Physics
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry


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