  The magnetic breakout model, in which reconnection in the corona leads to
destabilization of a filament channel, explains numerous features of eruptive
solar events, from small-scale jets to global-scale coronal mass ejections
(CMEs). The underlying multipolar topology, pre-eruption activities, and
sequence of magnetic reconnection onsets (first breakout, then flare) of many
observed fast CMEs/eruptive flares are fully consistent with the model.
Recently, we have demonstrated that most observed coronal-hole jets in
fan/spine topologies also are induced by breakout reconnection at the null
point above a filament channel (with or without a filament). For these two
types of eruptions occurring in similar topologies, the key question is, why do
some events generate jets while others form CMEs? We focused on the initiation
of eruptions in large bright points/small active regions that were located in
coronal holes and clearly exhibited null-point (fan/spine) topologies: such
configurations are referred to as pseudostreamers. We analyzed and compared
SDO/AIA, SOHO/LASCO, and RHESSI observations of three events. Our analysis of
the events revealed two new observable signatures of breakout reconnection
prior to the explosive jet/CME outflows and flare onset: coronal dimming and
the opening-up of field lines above the breakout current sheet. Most key
properties were similar among the selected erupting structures, thereby
eliminating region size, photospheric field strength, magnetic configuration,
and pre-eruptive evolution as discriminating factors between jets and CMEs. We
consider the factors that contribute to the different types of dynamic
behavior, and conclude that the main determining factor is the ratio of the
magnetic free energy associated with the filament channel compared to the
energy associated with the overlying flux inside and outside the pseudostreamer
dome.
