Department of Physics and Astronomy

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    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.
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    History of Physics & Astronomy at GMU 1966-2007
    (2007-11-14T16:22:09Z) Ehrlich, Robert
    A powerpoint presentation of the history of the Department 1966-2007
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    Animations of oscillations and waves
    (2007-12-02T05:49:37Z) Ceperley, Peter
    Animations of the physics of oscillations and waves. These are done in Adobe Flash, version SWF6.
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    Animation of phasor
    (2007-12-02T06:31:57Z) Ceperley, Peter
    Animation of geometric phasors (without use of complex numbers). The animation consists of a girl on the end of a bungy cord oscillating up and down. The explaining phasor diagram is also shown and connected to the girl's motion.
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    Animation of a complex rotor
    (2007-12-03T01:10:20Z) Ceperley, Peter
    Animation showing the time dependent behavior of the function exp(iwt). This is the central concept of representing oscillations and waves in complex forms.
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    Animation of complex oscillation
    (2007-12-03T01:17:26Z) Ceperley, Peter
    This animation shows the time dependent behavior of a phasor representing an oscillating object. It also displays an x-y graph (time is the x variable) of the oscillation and a bar graph of the oscillating variable. All are linked to change together.
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    Animation of a complex oscillation multiplied by a complex constant
    (2007-12-03T01:26:12Z) Ceperley, Peter
    This animation shows two phasors rotating in time in the complex plane. One phasor is a representation of an oscillation, and the other one is that oscillation multiplied by a complex constant. The animation also shows bar graphs of the two constants and also graphs them versus time. All three are shown to progressed together in time. This animation is directed towards students understanding of the dynamic nature of the complex phasors presented in text books.
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    Animation of Marconi's spark gap transmitter
    (2007-12-04T05:34:40Z) Ceperley, Peter
    Animation of the basics of Marconi's spark gap transmitter. Can be stepped to allow viewer to understand the sequence that allows it to work.
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    Animation of complex phasor representation of a traveling wave
    (2007-12-04T05:40:37Z) Ceperley, Peter
    Animation of the complex phasor representation of a traveling wave. This animation shows the time dependence of the complex phasor at various points along a one dimensional wave.
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    Animation of the shifting of a gaussian function
    (2007-12-04T05:49:12Z) Ceperley, Peter
    This animation illustrates the shifting of a gaussian function by substituting x-x0 in place of x. This is a preliminary for understanding the mathematical representation of a traveling wave.
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    Animation of a moving gaussian function
    (2007-12-04T05:56:29Z) Ceperley, Peter
    This animation shows the temporal behavior of a time shifting gaussian function. This is sometimes considered a solitary wave.
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    Animation of a traveling wave as a complex, helical phasor.
    (2007-12-04T06:02:27Z) Ceperley, Peter
    This animation shows the time dependence of the complex phasor representation of a one dimensional traveling wave. The wave is seen as a rotating helix.
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    Animation of a traveling wave as a cosine fuction.
    (2007-12-04T06:07:28Z) Ceperley, Peter
    This animation shows the time dependence of the cosine representation of a traveling wave.
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    Animation of adding phasors
    (2007-12-08T00:00:00Z) Ceperley, Peter
    This animation demonstrates the addition in time of two sinusoid signals added together by means of phasors. To make the concept connected to real objects, two bungy jumpers are used to connect the phasors with real oscillating objects.
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    Animation of beating of two sinusoids
    (2007-12-08T00:00:00Z) Ceperley, Peter
    This animation demonstrates the addition of two phasors rotating at different rates to produce a beating sinusoidal signal. To connect the process to real life, two bungy jumpers to provide the oscillating waveforms.
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    Phasor rotor
    (2007-12-08T00:00:00Z) Ceperley, Peter
    This animation shows the temporal behavior of an elemental rotor as is basic to the use and understanding of phasors. Phasors are heavily used in physics and electrical engineering to mathematically work with oscillations and waves of all types.
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    Animation of waves on a string
    (2007-12-19T04:51:21Z) Ceperley, Peter
    Animation of a simple one dimensional traveling wave. This animation shows a monkey creating traveling waves on a string.
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    Animation of two dimensional wave
    (2007-12-19T04:55:44Z) Ceperley, Peter
    Animation of a two dimensional wave propagating through a mesh. The wave is aligned with one of the axes.
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    Animation of a 2D oblique wave
    (2007-12-19T04:59:47Z) Ceperley, Peter
    Animation of a traveling wave propagating on a two dimensional mesh. The wave is propagating at an oblique angle to either of the mesh axes.
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    Animation of a two dimensional radial wave on a mesh
    (2007-12-19T05:03:14Z) Ceperley, Peter
    This animation shows the propagation of a radial wave on a two dimensional mesh.