Electrostatic trap mass spectrometers are disclosed that may comprise at least two parallel sets of electrodes separated by a field-free space, wherein said at least two parallel electrode sets extend along a curved Z-direction locally orthogonal to said X-Y plane such that each of said two electrode sets define a volume with a two-dimensional electrostatic field in an X-Y plane and define either planar or torroidal field regions; means for adjusting the torroidal field regions to provide both (i) stable trapping of ions passing between said fields within said X-Y plane and (ii) isochronous repetitive ion oscillations within said X-Y plane such that the stable ion motion does not require any orbital or side motion; and an ion bounding means in the curved Z-direction configured to compensate time-of-flight distortions at Z-edges of the trap.