Research, Department of Physics and Astronomy
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Item A Model Study of the Response of Mesospheric Ozone to Short-Term Solar Ultraviolet Flux Variations(American Geophysical Union, 1990-12-20T00:00:00Z) Summers, Michael E.; Strobel, D. F.; Bevilacqua, R. M.; Zhu, Xun; DeLand, M. T.; Allen, M.; Keating, G. M.An investigation is conducted in order to determine the relative importance of several modeled processes in controlling the magnitude and phase of the mesospheric ozone response. A detailed one-dimensional modeling study of the mesospheric ozone response to solar UV flux variations is conducted to remove some of the deficiencies in previous studies. This study is also used to examine specifically the importance of solar zenith angle, self-consistent calculation of water vapor abundance, and temperature feedback with a nonlocal thermodynamic equilibrium radiation model. The photochemical model is described, and the assumptions made for the purpose of comparing model results with the observed ozone response obtained from a statistical analysis of Solar Mesosphere Explorer data (Keating et al., 1987) are discussed. The numerical results for the theoretical ozone response are presented. The results of selected time-dependent calculations are considered to illustrate the degree to which a relatively simple model of the mesosphere is able to capture the major characteristics of the observed response.Item Album of flash animations, demonstrating oscillations, waves, and phasors(2008-01-08T03:08:08Z) Ceperley, PeterA album of 24 flash animation illustrating various principles of the physics of oscillations, waves, and phasors. The album shows an image of each animation and has various links to each.Item An unshielded radio-frequency atomic magnetometer with sub-femtoTesla sensitivity(AIP Publishing LLC, 2014-12-31) Keder, David A.; Prescott, David W.; Conovaloff, Adam W.; Sauer, Karen L.We demonstrate a radio-frequency potassium-vapor magnetometer operating with sensitivities of 0.3 fT/√Hz at 0.5 MHz and 0.9 fT/ √Hz at 1.31 MHz in the absence of radio-frequency and mu-metal or magnetic shielding. The use of spatially separated magnetometers, two voxels within the same cell, permits for the subtraction of common mode noise and the retention of a gradient signal, as from a local source. At 0.5 MHz the common mode noise was white and measured to be 3.4 fT/ √Hz; upon subtraction the noise returned to the values observed when the magnetometer was shielded. At 1.31 MHz, the common mode noise was from a nearby radio station and was reduced by a factor of 33 upon subtraction, limited only by the radio signal picked up by receiver electronics. Potential applications include in-the-field low-field magnetic resonance, such as the use of nuclear quadrupole resonance for the detection of explosives.Item Animated AM modulation diagram(2011-04-01T00:00:00Z) Ceperley, PeterThis animation shows the creation of a amplitude modulated signal with an animated block diagram.Item Item Animated seal to Joseph Fourier and Isaac Newton(2009-01-20T20:30:33Z) Ceperley, PeterThis animated seal portrays the essence of the common work my Isaac Newton and Joseph Fourier on the decomposition of waves into their sinusoidal components.Item Animation - phase in Fourier series(2009-02-26T05:26:43Z) Ceperley, PeterAn animation showing the effect of shifting the original function before taking a Fourier series expansion.Item Animation of a rotating 0,1 mode on a 2D circular resonator with Neumann boundaries(2016-03-07) Ceperley, PeterThis animation shows the time dependence of a two dimensional circular resonator with Neumann boundaries when excited in the 3,2 rotating mode.Item Animation of +111 rotating wave Neumann mode of cylindrical resonator with positive rotation(2016-02-09) Ceperley, PeterThis animation shows the time and space dependence of the +111 rotating wave Neumann mode of a cylindrical resonator with positive rotation.Item Animation of +211 rotating wave Dirichlet mode of cylindrical resonator showing interior fields(2016-02-09) Ceperley, PeterThis animation shows the time and space dependence of the interior fields of a +211 Dirichlet mode of a cylindrical resonator with positive rotation.Item Animation of +211 rotating wave Neumann mode of cylindrical resonator with positive rotation(2016-02-09) Ceperley, PeterThis animation shows the time and space dependence of the +211 rotating wave Neumann mode of a cylindrical resonator with positive rotation.Item Animation of -111 Neumann mode of cylindrical resonator having negative rotation(2016-02-09) Ceperley, PeterThis animation shows the time and space dependence of the -111 rotating wave Neumann mode of a cylindrical resonator.Item Animation of 0,1 mode on a 2D circular resonator with Dirichlet boundaries(2016-03-07) Ceperley, PeterThis animation shows the time dependence of a two dimensional circular resonator with Dirichlet boundaries when excited in the 0,1 mode.Item Animation of 0,1 mode on a 2D circular resonator with Neumann boundaries(2016-03-07) Ceperley, PeterThis animation shows the time dependence of a two dimensional circular resonator with Neumann boundaries when excited in the 0,1 mode.Item Animation of 010 Neumann mode of cylindrical resonator(2016-02-09) Ceperley, PeterThis animation shows the time and space dependence of the 010 Neumann mode of a cylindrical resonator.Item Animation of 011 Neumann mode of cylindrical resonator(2016-02-09) Ceperley, PeterThis animation shows the time and space dependence of the 011 Neumann mode of a cylindrical resonator. This mode is not capable of showing rotation.Item Animation of 1,1 mode on a 2D circular resonator with Neumann boundaries(2016-03-07) Ceperley, PeterThis animation shows the time dependence of a two dimensional circular resonator with Neumann boundaries when excited in the 1,1 mode.Item Animation of 110 Neumann mode of cylindrical resonator(2016-02-09) Ceperley, PeterThis animation shows the time and space dependence of the 110 Neumann mode of a cylindrical resonator.Item Animation of 221 Neumann mode of cylindrical resonator(2016-02-09) Ceperley, PeterThis animation shows the time and space dependence of the 221 Neumann mode of a cylindrical resonator.Item Animation of 221 Neumann mode of cylindrical resonator with negative rotation(2016-02-09) Ceperley, PeterThis animation shows the time and space dependence of a rotating 221 Neumann mode of a cylindrical resonator with negative rotation