  Impulsive solar energetic-particle (SEP) events were first distinguished as
the streaming electrons that produce type III radio bursts as distinct from
shock-induced type II bursts. They were then observed as the
surprisingly-enhanced 3He-rich SEP events, which were also found to have
element enhancements rising smoothly with the mass-to-charge ratio A/Q through
the elements, even up to Pb. These impulsive SEPs have been found to originate
during magnetic reconnection in solar jets where open magnetic field lines
allow energetic particles to escape. In contrast, impulsive solar flares are
produced when similar reconnection involves closed field lines where energetic
ions are trapped on closed loops and dissipate their energy as X-rays,
{\gamma}-rays, and heat. Abundance enhancements that are power-laws in A/Q can
be used to determine Q values and hence the coronal source temperature in the
events. Results show no evidence of heating, implying reconnection and ion
acceleration occur early, rapidly, and at low density. Proton and He excesses
that contribute their own power-law may identify events with reacceleration of
SEPs by shock waves driven by accompanying fast, narrow coronal mass ejections
(CMEs) in many of the stronger jets.
