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For understanding the physics of energetic particles, the deuterium experimental campaignsstarted in Large Helical Device (LHD) from March 2017. To investigate the behavior ofenergetic particles, a Fast-ion D Alpha (FIDA) diagnostic was installed on the LHD. In theFIDA diagnostic, the Doppler-shifted D alpha light from fast-neutrals are utilized as signals ofenergetic particles, where these fast-neutrals are produced by the charge exchange processbetween fast-ions in the plasma and actively injected neutrals by neutral beam (NB). Theadvantages of the FIDA diagnostic are the velocity and the spatially resolved measurement offast-ions at the crossing point between its line of sight (LOS) and the incident line of NB. Themost recent FIDASIM is enhanced to simulate signals produced in three-dimensional magneticconfigurations. The new version of FIDASIM uses the fast-ion distribution function producedby GNET as input to simulate FIDA signals at LHD. In order to validate the new version of thecode, measurements of radial profiles of fast-ions using the FIDA diagnostic are performed inmagnetohydrodynamic (MHD)-quiescent plasmas. The measured spectra are in good agreementwith the theoretical prediction by 3D-supporting FIDASIM at the center of the plasma(R = 3.5 m~3.7 m, reff/a99 = −0.28~0.05) on the LHD when the line averaged electron densityis ne_avg < 1.23 × 1019 m−3. On the other hand, the measured spectra are in disagreement withthe theoretical prediction by 3D-supporting FIDASIM at even the center of the plasma when theline averaged electron density is ne_avg ≥ 1.23 × 1019 m−3., source:Citation Y. Fujiwara et al 2020 Nucl. Fusion 60 112014, source:https://doi.org/10.1088/1741-4326/abae84, identifier:0000-0003-2985-060X

Understanding the effect of Alfvén eigenmodes (AEs) and neoclassical tearing modes (NTMs) on fast ions is highly important for fusion reactors due to potentially strong resonant interactions between the fast ions and the modes. Here, we use the four-view fast-ion D-alpha (FIDA) diagnostic installed in the DIII-D tokamak to reconstruct the fast-ion velocity distribution at two radial positions during two sequential discharges with strong and weak mode activity, respectively. The velocity-space coverage of the diagnostics, however, only allows reliable reconstructions of fast ions with positive pitches. Therefore, we suggest new tomographic inversion methods relying on prior information outside the well-diagnosed region. We find that within the population of fast ions with positive pitches, ions, at all energies, are transported away from the measurement volumes. Comparisons between the reconstructions and kick model simulations, where the mode activity is considered, reveal that low-frequency modes such as the NTMs and low-frequency AEs contribute significantly to the positive-pitch fast-ion transport in the central measurement volume, whereas TAEs and EAEs become important farther out and are responsible for decreased fast-ion confinement.

The present study examined 7- to 11-month-old infants' anticipatory and reactive reaching for temporarily occluded objects. Infants were presented with laterally approaching objects that moved at different velocities (10, 20, and 40. cm/s) in different occlusion situations (no-, 20. cm-, and 40. cm-occlusion), resulting in occlusion durations ranging between 0 and 4. s. Results show that except for object velocity and occlusion distance, occlusion duration was a critical constraint for infants' reaching behaviors. We found that the older infants reached more often, but that an increase in occlusion duration resulted in a decline in reaching frequency that was similar across age groups. Anticipatory reaching declined with increasing occlusion duration, but the adverse effects for longer occlusion durations diminished with age. It is concluded that with increasing age infants are able to retain and use information to guide reaching movements over longer periods of non-visibility, providing support for the graded representation hypothesis (Jonsson & von Hofsten, 2003) and the two-visual systems model (Milner & Goodale, 1995). © 2010 Elsevier Inc.