CORRELATED OSCILLATIONS AND THEIR RF SPECTRA DETECTABILITIES OF 2 OPPOSITELY CHARGED THERMAL ION CLOUDS IN A PAUL TRAP

A symmetric expression is derived for the coulombic interaction betwee n two species of thermal ions trapped in a r.f. trap. Consequently, th e oscillation frequencies of the weak and the strong oscillation modes of the system and their relevant conditions are expressed quantitativ ely. When two kinds of oppositely charged ions are trapped, a strong c oupling region near a strong correlation line always exists, so that t he coupling type can be controlled by selecting a suitable operation p oint. The detectability and the evolution of the electrical signals by r.f. resonance absorption detection are also discussed.