  Microparticles ranging from sub-microns to millimeter in size are a common
form of matter in magnetic fusion environment, and they are highly mobile due
to their small mass. Different forces in addition to gravity can affect their
motion both inside and outside the plasmas. Several recent advances open up new
diagnostic possibilities to characterize the particle motion and their forces:
high-speed imaging camera technology, microparticle injection techniques
developed for fusion, and image processing software. Extending our earlier work
on high-temperature 4D microparticle tracking using exploding wires, we report
latest results on time-resolved microparticle acceleration measurement. New
particle tracking algorithm is found to be effective in particle tracking even
when there are a large number of particles close to each other. Epipolar
constraint is used for track-pairing from two-camera views. Error field based
on epi-geometry model is characterized based on a large set of 2D track data
and 3D track reconstructions. Accelerations based on individual reconstructed
3D tracks are obtained. Force sensitivity on the order of ten gravitational
acceleration has achieved. High-speed imaging is a useful diagnostic tool for
microparticle physics, computer model validation and mass injection technology
development for magnetic fusion.
