Browsing by Author "Young, David T."

Now showing 1 - 3 of 3
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    Observations of dayside magnetopause oscillations and concurrent temporal variations in cusp precipitation
    (1999) Dempsey, Donna Lynn; Young, David T.
    On April 13, 1996, while Russia's Interball Tail spacecraft was travelling through the dayside magnetosheath, NASA's Polar spacecraft traversed the northern cusp. Transients observed in the data from the Interball Tail/SCA-1 particle instrument are shown to be multiple crossings of the magnetopause. Analysis of data from the SCA-1 instrument and magnetic field data from the MIF instrument shows quasi-periodic motions of the magnetopause. Simultaneous observations of changes in cusp precipitation by the Polar/TIDE instrument and changes in the He2+/H+ density ratio in the cusp by the Polar/TIMAS instrument show variations on the same time scale. We show that the variations in the cusp data observed by Polar are the result of changes in the reconnection rate at the magnetopause and that these changes are associated with the magnetopause oscillations observed by Interball.
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    Optical development of an ion/electron acceleration facility
    (1998) Dempsey, Donna Lynn; Young, David T.
    This thesis details the optical development of an ion/electron accelerating facility at Southwest Research Institute which is currently being used to calibrate the Plasma Spectrometer for the Cassini Mission to Saturn. The optical development involves particle (ion) ray tracing of each element in the facility in order to computationally determine the focusing and mass separating parameters of each of the elements. This computational data is then compared with the actual output beam from the accelerating facility. The behavior of each of the elements is determined and its affect on the output beam is established. Changes to the design of the facility can then be made based upon this information.
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    Simulation and Optimization of ESA Designs for Space Plasma Missions
    (2011) Gomez, Roman G.; Young, David T.
    A novel electrostatic analyzer (ESA) simulation method that differs significantly from traditional methods is presented in this study, the "reverse-fly" simulation method. The simulation process and its applications are discussed in detail. This method is tested by comparing its results to the published test data of three experimental instruments; The Proton Electrostatic Analyzer-High Geometric Factor (PESA-H) instrument on the Wind mission [Lin, et al. 1995], the 2π-Toroidal Analyzer (2πTA) of Young, et al., [1988], and the Hot Plasma Composition Analyzer (HPCA) to be used in the upcoming Magnetospheric Multi-scale (MMS) mission. The strong agreement between simulation and experimental results verifies the accuracy of this technique. Our results reveal detailed properties of ESA response that are not practical to assess using laboratory data. This simulation method then is used to compare the transmission characteristics of five published ESA geometries to efficiently determine the optimal ESA geometry for use in future space missions. We show that the simulation methods described here are an important contribution to instrument design and development techniques and are critical to efficient and accurate verification of instrument performance.