Space charge and collective oscillation of ion cloud in a linear Paul trap

The presence of charged particles in an ion trap modifies the harmonic trapping potential in which they are trapped, leading to observed shifts in secular frequency as well as appearance of collective oscillation. In a linear trap geometry, both of these effects have been observed under different trapping conditions using narrow non-linear resonance and external excitation. The observations have been modeled with minimal fitting parameter showing good agreement with results obtained. The space charge in our experiment plays an important role in terms of criticality of the onset of collective oscillation.