• V.D. Shiltsev, G.F. Kuznetsov, A. Valishev
  Fermilab, Batavia
• V. Kamerdzhiev
  FZJ, Jülich
• A.L. Romanov
  BINP SB RAS, Novosibirsk

We report preliminary results of experimental studies of "electron columns" in the Tevatron and in a specialized test setup. In the Tebvatron, 150 GeV beam of protons ionized residual gas and ionization electrons are stored in an electrostatic trap immersed into strong longitudinal magnetic field. Shifts of proton betatron frequencies are reported. In the test set, we observe effects pointing to accumulation and escape of ionization electrons.