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Department Library

1971

William Dean Daily (PhD Dissertation, August 1971, Advisor: Jae Ballif )

Abstract

A dispersion equation is derived for propagation of plasma waves in a non-uniform external magnetic field. Its solution assumes that when the field is inhomogeneous only first order small changes will occur in the wave parameters and the guiding center approximation is used to calculate these changes. The equations are applied to the problem of Alfven wave propagation in interplanetary space for longitudinal gradients in the external field and numerical solutions are presented.

1970

Stacy Wenzel Luke (PhD Dissertation, January 1970, Advisor: Jae Ballif )

Abstract

The possible interplanetary origin of 2-8 min micro-pulsations in the earth’s magnetic field is explored. Power spectra obtained from the Mariners II, IV and V magnetic data are compared with micro-pulsations observed on the earth a College, Alaska; Reykjavik, Iceland; and Sodankyla, Finland. An approximate one to one correspondence is found between the periods of micro-pulsations in the earth’s magnetic field and the periods of oscillations in the interplanetary magnetic field. A dispersion equation is derived to show that these periodic oscillations in the interplanetary magnetic field could be transverse waves propagating along field lines. Damping lengths of 1011 meters to over 1099 meters are obtained. It is suggested from the evidence of the study that waves in the interplanetary medium interact with the geomagnetic field generating micro-pulsations of approximately the same period.

Darrell Smith (Masters Thesis, August 1970, Advisor: Jae Ballif )

Abstract

Although it is generally accepted that large single flares cause Forbush decreases, previous studies have shown that a large single flare does not necessarily occur near the time of a cosmic ray decrease. The purpose of this study was to show that there is statistical evidence over a period of on solar cycle that cosmic ray decreases relate instead to solar fare-producing regions. Epoch analysis was used to study cosmic ray decreases defined by three different criteria. Major cosmic ray decreases observed at high latitudes were found to begin near the time that a flare-producing region on the sun passes central meridian. This significant relationship was found to hold even for the best-documented Forbush decreases as given by Webber. Most flare-producing regions, that relate to high latitude cosmic ray decreases in both the north and south ho the earth, originate between zero and 30 degrees in north latitude on the sun. Evidence for a 27-day recurrence pattern is observed in both the cosmic ray and solar flare data.

Donald A. Steele (Masters Thesis, August 1970, Advisor: Jae Ballif )

Abstract

A study of 9.1 cm solar radio emission and flare producing regions was made for events that occurred from January 1965 to July 1968. Cosmic ray decreases and the intensity of 9.1 cm solar radio emission were also compared for this period. A close relationship exists between two solar variables during this time interval. The slowly varying component of the 9.1 cm emission and the total flare count from flare producing regions have essentially a one to one relationship. From time to time, a one-day lead in brightness temperature over total flare counts is observed. The part to importance 2 or greater flares occurring within the source region. Of the 41 cosmic ray decreases observed during this interval only three could not be easily associated with an increase in brightness temperature near solar central meridian.

1969

Rick Karl Skousen (Masters Thesis, January 1969, Advisor: Jae Ballif )

Abstract

A study of the relationship between flare-producing regions and cosmic-ray decreases was undertaken for the period of February, 1967, to July, 1968. Neutron monitor and meson telescope cosmic-ray data and grouped solar-flare data were used in the study. Studies of solar flares and cosmic-ray decreases have shown that a large, individual flare does not necessarily occur near the time of a cosmic-ray decrease. However, by identifying flare-producing regions, it was shown in this study that for every neutron monitor cosmic-ray decrease of ≥1%, a flare-producing region was observed to be near the central meridian of the sun. Anisotropies in the cosmic-ray data, north and south of the ecliptic plane, were seen. High latitude flare-producing regions north or south of the solar sub-terrestrial point were present near the central meridian of the sun near the time when cosmic-ray decreases were detected by the meson telescopes, north or south of the earth’s equator. The question of a latitude effect, in which flare-producing regions above or below a certain solar latitude were not related to cosmic-ray decreases is unresolved.

1968

Carl Smyth Christensen (Masters Thesis, August 1968, Advisor: Jae Ballif )

Abstract

Solar cosmic ray observations are used to investigate the interplanetary magnetic field. The general spiral interplanetary magnetic field, as well as various models for features of this general field, are introduced. The effects that a magnetic field might have on the path of energetic solar particles are summarized. Observations of solar cosmic rays are then reviewed; these include generalizations derived from polar cap absorption and relativistic ground level events as well as satellite and spacecraft measurements. The occurrence of ground level events relative to geomagnetic activity is studied; a tendency for these events to avoid the hours of greatest geomagnetic activity is noted. These generalization are then used to evaluate the previously introduced ideas and models of the interplanetary field. The following conclusions and suggestions are made. Many of the observed longitudinal asymmetries of cosmic ray flares are explicable in terms of a spiral interplanetary magnetic field and cosmic rays which travel more easily along the field lines than across them. The delays and anisotropies observed in the arrival of solar cosmic rays may be indicative of the number of magnetic irregularities the particles have encountered between the flare site and their point of detection. Low energy solar cosmic ray data suggests that broad corotating magnetic field regions emanate from solar active regions. It may be that not all solar cosmic rays are accelerated by flares. Not all aspects of the solar cosmic ray data are compatible with interplanetary disturbance models which postulate either: (1) that the flare which emits the cosmic rays also impulsively ejects a cloud or shell; or (2) that the interplanetary disturbance pre-exists at the time of the flare, with the flare only emitting solar cosmic rays.

John Burton Winters (Masters Thesis, January 1968, Advisor: Jae Ballif )

Abstract

Interplanetary magnetic field measurements of the Mariner 4 satellite were compared with the solar photospheric magnetic field features measured at the Mt. Wilson Observatory from December 1964 through April 1965. For comparison with the photospheric magnetic field along the ideal spiral angel was considered. This gave an indication of the direction of the interplanetary field. Three types of parameters were chosen. This provided a measure of: (1) the magnitude and direction of the interplanetary and photospheric fields; (2) the absolute magnitude of the interplanetary and photospheric fields; and (3) the direction of the interplanetary and photospheric magnetic field. Correlation studies were made with the two sets of data. There were no significant correlations found between the interplanetary and photospheric magnetic field parameters at times consistent with the travel time (about 5 days according to Mariner 4 plasma velocity data) of plasma particles from the photospheric region. The results of precious workers were not verified during the time period of this study with regard to the correlation of the interplanetary and photospheric magnetic field directions. A qualitative comparison of individual interplanetary and photospheric magnetic field features showed good correspondence for many time periods. Several events of high interplanetary magnetic fields appeared to have their origin on the photosphere at times when the whole photosphere disk was unipolar in nature.

1966

Bruce K Carter (Masters Thesis, May 1966, Advisor: Jae Ballif )

Abstract

An evaluation of a general education program in the physical sciences necessitates a determination of the information level of the student in the program. This evaluation should also include an analysis of differences between the information levels of students of physical science and those of other disciplines. The level of information of the student as a measure of success of a program is based on the definition that general education should help the student understand his interaction with his inanimate surroundings and prepare him for appreciative and creative living. The most effective method of determination or testing of this information level is the oral or essay examination. However, because of its impracticality for the purposes of this study, multiple choice questions were developed realizing that they were limited in their ability to test the recall of information. These questions were developed around the most basic or gross concepts in physical sciences. Possible answers were included, the selection of which would indicate the currentness of information of the student. Also include were questions which determined the factual information of the student. A sample of the population of juniors and seniors attending Brigham Young University during the spring semester 1965 was selected at random. The size of the sample was determined by the desired confidence level and variance. The high percentage of recovery of the questionnaires insured a confidence level of at least ninety-five with a variance of ten. The results of this study indicate that the general education program in physical science at Brigham Young University is not as successful as it should be. Generally, the sample understood some facts and concepts very well. But other concepts were not as well understood. The concepts least understood were those which have been developed since 1900. A statistically significant proportion of the sample answered all but five of the items of the questionnaire incorrectly. In some cases, this proportion was a majority of the sample. Analysis included a comparison of various combinations of classes taken by the sample and the answers given. The results indicated that taking one combination was no more beneficial than taking another. Also included was a determination of any difference between physical science majors and non-majors. As expected, a significant difference favors the majors which is very disappointing to the investigator.

1965

Bruce K. Carter (Masters Thesis, January 1965, Advisor: Jae Ballif )

Abstract

An evaluation of a general education program in the physical sciences necessitates a determination of the information level of the student in the program. His evaluation should also include an analysis of difference between the information levels of students of physical science and those of other disciplines. The level of information of the student as a measure of success of a program is based on the definition that general education should help the student understand his interaction with his inanimate surroundings and prepare him for appreciative and creative living. The most effective method of determination or testing of this information level is the oral or essay examination. However, because of its impracticality for the purposes of this study, multiple choice questions were developed realizing that they were limited in their ability to test the recall of information. These questions were developed around the most basic or gross concepts in physical sciences. Possible answers were included, the selection of which would indicate the currentness of information of the student. Also included were questions which determined the factual information of the student. A sample of the population of juniors and seniors attending Brigham Young University during the spring semester 1965 was selected at random. The size of the sample was determined by the desired confidence level and variance. The high percentage of recovery of the questionnaires insured a confidence level of at least ninety-five with a variance of ten. The results of this study indicate that the general education program in physical science at Brigham Young University is not as successful as it should be. Generally, the sample understood some facts and concepts very well. But other concepts were not as well understood. The concepts least understood were those which have been developed since 1900. A statistically significant proportion of the sample answered all but five of the items of the questionnaire incorrectly. In some cases, this proportion was a majority of the sample. Analysis included a comparison of various combinations of classes taken by the sample and the answers given. The results indicated that taking one combination was no more beneficial than taking another. Also included was a determination of any difference between physical science major and non-majors. As expected, a significant difference favors the majors, which is very disappointing to the investigator.

Don Morris Wrathall (Masters Thesis, May 1965, Advisor: Jae Ballif )

Abstract

Design details are given for the construction of a simple, portable but sensitive photometric system for recording the nocturnal variation of thesodium-D2 emission from the night sky. A brief review of airglow characteristics is included. A five inch objective lens is employed as the entrance pupil. Radiation converging from the objective is rendered parallel by a diverging lens before impinging upon a Baird-Atomic multilayer interference filter. An RCA 1P21 photomultiplier tube is used for the detector. Its output, of the order of 10-9 ampere for typical nightglow intensity, is amplified by a Keithley, battery operated, electrometer and then, drives a magnetic amplifier followed by an Esterline-Angus strip chart recorder. The total field of view as measured by the passage time of a star through it is about five degrees square. A preliminary calibration of 2.2 rayleighs (emission rate) per scale division was done by comparing the radiation reflected from the planet, Venus to that of the sun. Typical measurements of the Na-D2 emission during the months of July, August, and September show a steady decrease through the night with an average emission rate of about 21 rayleighs. Wintertime measurements give an indication of a decline in intensity during the first part of the night, and then a rise before dawn.

1964

Douglas Emron Jones (PhD Dissertation, August 1964, Advisor: Jae Ballif )

Abstract

Abroad the Mariner R II spacecraft was a duel channel microwave radiometer which obtained three scans across the planet Venus at wavelengths of 13.5 and 19 millimeters. The relationship of the peak temperature values of the three scans supports a hot surface model of the planet. Several atmosphere-surface configurations were assumed in an attempt to match the limb darkening ratios and temperature values measured at both wavelengths. The model which agrees most closely with the data is one which consists of a specular surface and an isothermal cloud type layer at a temperature of near 350oK. The anomaly which occurred toward the end of scan 2 was in the same region of the planet as that observed by the terrestrial measurements at 8-14 μ and is consistent with a marked increase in opacity of the 350oK cloud layer in this region. The marked difference between 13.5 and 19mm temperatures indicate the presence of an abrupt discontinuity in the microwave spectrum of Venus which cannot be due to uncondensed water vapor and hence requires the presence of a molecule or molecules in the atmosphere of Venus which condense or polymerize into liquid form at T≥350 oK and exhibit line spectra in the vicinity of 13.5 millimeters and short ward. The magnitude of the relative dielectric coefficient of the surface is found to lie between 3 and 4. The surface temperature variation which best fits the data is of the form TS = 700oK + (75-85)oKcos⁡∅. An upper limit of ~ 100 atmospheres for the surface pressure is obtained for an atmosphere containing 20% CO2 and 80% N2.