"Slow LDEs" are those for which the rise phase is slow, as well as the
decay phase. We confirm that such flares adhere to the Neupert effect,
which implies that the level of non-thermal energy release has the same
proportion to heating as in a normal impulsive flare. We identify a sample
of 53 slow LDEs during the Yohkoh interval, and find 19 for which
substantial overlap occurs with BATSE hard X-ray observations. As expected
from the Neupert effect, these events tend to have extended hard X-ray
emission. The hard X-ray fluences for these 19 events correlate with the
soft X-ray peak fluxes, suggesting that particle acceleration tends to be
independent of energy-release rate in the rise phase. We also find that
these events often correspond to the occurrence of "supra-arcade
downflows," a phenomenon consistent with the classical reconnection model
for gradual-phase flare energy release.
What do these observations imply for large-scale reconnection models?