Editing Coronal mass ejection (section)

====Initial acceleration====
Following initiation, CMEs are subject to different forces that either assist or inhibit their rise through the lower corona. Downward [[magnetic tension]] force exerted by the strapping magnetic field as it is stretched and, to a lesser extent, the gravitational pull of the Sun oppose movement of the core CME structure. In order for sufficient acceleration to be provided, past models have involved magnetic reconnection below the core field or an ideal MHD process, such as instability or acceleration from the solar wind.

In the majority of CME events, acceleration is provided by magnetic reconnection cutting the strapping field's connections to the photosphere from below the core and outflow from this reconnection pushing the core upward. When the initial rise occurs, the opposite sides of the strapping field below the rising core are oriented nearly [[Euclidean vector#Opposite, parallel, and antiparallel vectors|antiparallel]] to one another and are brought together to form a [[current sheet]] above the PIL. Fast magnetic reconnection can be excited along the current sheet by microscopic instabilities, resulting in the rapid release of stored magnetic energy as kinetic, thermal, and nonthermal energy. The restructuring of the magnetic field cuts the strapping field's connections to the photosphere thereby decreasing the downward magnetic tension force while the upward reconnection outflow pushes the CME structure upwards. A [[positive feedback loop]] results as the core is pushed upwards and the sides of the strapping field are brought in closer and closer contact to produce additional magnetic reconnection and rise. While upward reconnection outflow accelerates the core, simultaneous downward outflow is sometimes responsible for other phenomena associated with CMEs (see {{slink||Coronal signatures}}).

In cases where significant magnetic reconnection does not occur, ideal MHD instabilities or the dragging force from the solar wind can theoretically accelerate a CME. However, if sufficient acceleration is not provided, the CME structure may fall back in what is referred to as a ''failed'' or ''confined eruption''.<ref name=aschwanden19 /><ref name=chen11 />