Ultraviolet-visible-near infrared spectra of 50 samples (open access)

Ultraviolet-visible-near infrared spectra of 50 samples

Under the subject contract, Unidynamics/Phoenix recorded the ultraviolet-visible-near infrared spectra of 50 samples supplied by LANL. A Varian Cary 2300 series spectrophotometer produced the spectral data. The spectrophotometer was interfaced to a Varian D5-15 Data Station, and hard copies of data were made. Baseline corrections throughout the wavelength range were established using Halon as a reference material. Corrected measurements were automatically made by the system on every sample. Two types of sample holders were tried. Before collecting data on the LANL samples, identical samples of PETN were examined using both holders.
Date: August 30, 1988
Creator: Taylor, B.
Object Type: Report
System: The UNT Digital Library
Magnetic reconnection simulation using the 2. 5D em (electromagnetic) direct implicit code AVANTI (open access)

Magnetic reconnection simulation using the 2. 5D em (electromagnetic) direct implicit code AVANTI

Collisionless reconnection of magnetic field lines depends upon electron inertia effects and details of the electron and ion distribution functions, thus requiring a kinetic description of both. Though traditional explicit PIC techniques provide this description in principle, they are severely limited in parameters by time step constraints. This parameter regime has been expanded by using the recently constructed 2.5 D electromagnetic code AVANTI in this work. The code runs stably with arbitrarily large {Delta}t and is quite robust with respect to large fluctuations occurring due to small numbers of particles per cell. We have found several qualitatively new features. The reconnection process is found to occur in distinct stages: early spontaneous reconnection fed by the free energy of an initial anisotropy in the electron component, coalescence of the resulting small-scale filaments of electron current, accompanied by electron jetting, and oscillatory flow of electrons through the magnetic X-point, superposed on continuing nonlinear growth of ion-mediated reconnection. The time evolution of stage is strongly dependent on M{sub i}/m{sub e}. 12 refs., 6 figs.
Date: August 30, 1988
Creator: Hewett, D. W.; Francis, G. E. & Max, C. E.
Object Type: Article
System: The UNT Digital Library