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Utah State University

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1982

Articles 1 - 7 of 7

Full-Text Articles in Physics

Predicted Diurnal Variations Of Electron Density For Three High-Latitude Incoherent Scatter Radars, Jan Josef Sojka, Robert W. Schunk Jan 1982

Predicted Diurnal Variations Of Electron Density For Three High-Latitude Incoherent Scatter Radars, Jan Josef Sojka, Robert W. Schunk

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We have used a high‐latitude ionospheric model to predict the diurnal variations of electron density that should be observed by the EISCAT, Chatanika and Millstone Hill incoherent scatter facilities. Our calculations were for a strong convection model without substorms. Our results provide an indication of the quantitative differences in measured electron density that are expected when the three radars probe the high‐latitude ionosphere simultaneously. The differences are significant and vary with altitude, latitude, local time, and season, and are associated with the UT dependence of the high‐latitude ionosphere which results from the displacement between the geomagnetic and geographic poles.

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The Role Of Diffusion In The Binding Of Carbon Monoxide To Protoheme In High-Viscosity Solvents, David Peak Jan 1982

The Role Of Diffusion In The Binding Of Carbon Monoxide To Protoheme In High-Viscosity Solvents, David Peak

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Studies of the flash photolysis of heme‐bearing proteins have often assessed the role of ligand diffusion in very approximate ways and a disagreement about the importance of ligand diffusion exists in the literature as a result. This paper provides a somewhat more sytematic analysis of diffusional effects than has been given previously for the simple case of ligand–protoheme binding. The model developed here is fit to the available data for the ligand CO in glycerol–water solvents. The fit suggests that diffusional motions become important for the kinetics of this system for temperatures below 270 K and that these motions are …

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Ionospheric Hot Spot At High Latitudes, Robert W. Schunk, Jan Josef Sojka Jan 1982

Ionospheric Hot Spot At High Latitudes, Robert W. Schunk, Jan Josef Sojka

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A hot spot (or spots) can occur in the high‐latitude ionsophere depending on the plasma convection pattern. The hot spot corresponds to a small magnetic local time‐magnetic latitude region of elevated ion temperatures located near the dusk and/or dawn meridians. For asymmetric convection electric field patterns, with enhanced flow in either the dusk or dawn sector of the polar cap, a single hot spot should occur in association with the strong convection cell. However, on geomagnetically disturbed days, two strong convection cells can occur, and hence, two hot spots should exist. The hot spot should be detectable when the electric …

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Seasonal Variations Of The High-Latitude F Region For Strong Convection, Jan Josef Sojka, Robert W. Schunk, W. John Raitt Jan 1982

Seasonal Variations Of The High-Latitude F Region For Strong Convection, Jan Josef Sojka, Robert W. Schunk, W. John Raitt

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We combined a plasma convection model with an ionospheric-atmospheric composition model in order to study the seasonal variations of the high-latitude F region for strong convection. Our numerical study produced time-dependent, three-dimensional, ion density distributions for the ions NO+, O2 +, N2 +, O+, N+, and He+. We covered the high-latitude ionosphere above 42°N magnetic latitude and at altitudes between 160 and 800 km for a time period of one complete day. From our study we found the following: (1) For strong convection, the high-latitude ionosphere exhibits a significant UT variation both during winter and summer. (2) In general, the …

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Ion Temperature Variations In The Daytime High-Latitude F Region, Robert W. Schunk, Jan Josef Sojka Jan 1982

Ion Temperature Variations In The Daytime High-Latitude F Region, Robert W. Schunk, Jan Josef Sojka

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We improved our high-latitude ionospheric model by including thermal conduction and diffusion-thermal heat flow terms in the ion energy equation so that we could study the ion temperature variations in the daytime high-latitude F layer in a region poleward of the auroral oval for steady state conditions at local noon. From our study we found that (1) The variation of Ti with solar cycle, season, and geomagnetic activity closely follows the Tn variation. The general trend is for higher temperatures in summer than in winter, at solar maximum than at solar minimum, and for active magnetic conditions than for quiet …

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Observations Of The Diurnal Dependence Of The High-Latitude F Region Ion Density By Dmsp Satellites, Jan Josef Sojka, W. John Raitt, Robert W. Schunk, F. J. Rich, R. C. Sagalyn Jan 1982

Observations Of The Diurnal Dependence Of The High-Latitude F Region Ion Density By Dmsp Satellites, Jan Josef Sojka, W. John Raitt, Robert W. Schunk, F. J. Rich, R. C. Sagalyn

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Data from the DMSP F2 and F4 satellites for the period December 5-10, 1979, have been used to study the diurnal dependence of the high-latitude ion density at 800-km altitude. A 24-hour periodicity in the minimum orbital density (MOD) during a crossing of the high-latitude region is observed in both the winter and summer hemispheres. The phase of the variation in MOD is such that it has a minimum during the 24-hour period between 0700 and 0900 UT. Both the long term variation of the high-latitude ion density on a time scale of days, and the orbit by orbit variations …

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Cyclotron Resonance Effects On Stochastic Acceleration Of Light Ionospheric Ions, Nagendra Singh, Robert W. Schunk, Jan Josef Sojka Jan 1982

Cyclotron Resonance Effects On Stochastic Acceleration Of Light Ionospheric Ions, Nagendra Singh, Robert W. Schunk, Jan Josef Sojka

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Numerical studies on the interaction of electrostatic hydrogen cyclotron (EHC) waves with light ionospheric ions, such as He+, show that when the wave number ratio k⊥/kll ≤ 10 resonant effects are important in the stochastic heating of the ions. When k⊥/kll > 10 an appreciable acceleration occurs even though the cyclotron‐resonant effects are absent. As the parallel wave number increases, causing k⊥/kll to decrease (< 10), the number of accelerated ions and the perpendicular and parallel energization increase.

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