The original objectives of this thesis were to use the new PolarDARN radars to study the convection patterns at high latitudes and to attempt to explain them in terms of reconnection. Because the IMF is important in reconnection, studies of the Interplanetary Magnetic Field (IMF) components Bx, By and Bz were done. The study showed that <|Bz|> was lower by 21.5% than <|By|> from Jan. 2006 to Dec. 2008, so By was expected to play an important role in reconnection. The IMF, spiral angle, and the amount of warping of the solar magnetic field in interplanetary space decreased slightly during this 36-month period. The decrease in IMF was a more sensitive indicator of the solar minimum than the decrease in the 10.7 cm solar microwave flux.<p> A solar magnetic sector boundary study from the Jan 1, 2007 Dec 31, 2008 interval showed the occurrence of four or two sectors in a synodic solar rotation cycle. A sector boundary crossing frequently takes place in less than 3 hours. The transition from four sectors to two sectors is surprisingly smooth, in that no interruption in the 27-day synodic period occurs. A superposed epoch analysis of solar wind speed near sector boundary crossings showed a speed minimum about half a day before the crossing, and a maximum about two days after the crossing. The standard deviation reached a minimum at about the same time as the velocity. The sector boundary study also showed that, since Dec. 2007, there were six roughly 27-day synodic solar rotation cycles near spring equinox when away field dominated, and that the following seven 27-day cycles close to the autumnal equinox were dominated by toward field. This is consistent with the quasi-sinusoidal annual magnetic sector polarity oscillations that occur for about three years during solar minimum. These oscillations are due to the mainly dipolar magnetic field which is roughly aligned with the Suns axis, tilted 7.25° from the normal to the ecliptic plane. The three-year oscillation for the present minimum between Solar Cycles 23 and 24 appeared to begin in Dec. 2007. For the past four solar minima, an El Nino event has occurred during the last of the three oscillations, and the El Nino and sinusoidal magnetic oscillation ended together. The new solar cycle began about 6 months before that. During the past eight years, a new 3D topological null-separator formulation of magnetic reconnection and its effect on convection has been led by Dr. M. Watanabe in ISAS at the University of Saskatchewan. This formulation includes two types of interchange reconnection (Russell and Tanaka) as well as the traditional Dungey reconnection. For conditions when the IMF clock angle was within 30° of a Bz+ dominant convection, the new reconnection model shows that the convection can be driven strictly by the two types of interchange reconnection. The model predicts the existence of a reciprocal cell on closed field lines and an interchange merging cell surrounding an interior lobe cell. The construction of the PolarDARN radars at Rankin Inlet and Inuvik, completed in December, 2007, allowed polar cap convection to be measured for predominantly Bz+ conditions. The existence of the two predicted features was confirmed. This also required that satellite data be analyzed to determine the location of the open-closed-field-line-boundary (OCFLB). Several PolarDARN studies are represented to show convection for different IMF clock angles and seasons.

The original objectives of this thesis were to use the new PolarDARN radars to study the convection patterns at high latitudes and to attempt to explain them in terms of reconnection. Because the IMF is important in reconnection, studies of the Interplanetary Magnetic Field (IMF) components Bx, By and Bz were done. The study showed that <|Bz|> was lower by 21.5% than <|By|> from Jan. 2006 to Dec. 2008, so By was expected to play an important role in reconnection. The IMF, spiral angle, and the amount of warping of the solar magnetic field in interplanetary space decreased slightly during this 36-month period. The decrease in IMF was a more sensitive indicator of the solar minimum than the decrease in the 10.7 cm solar microwave flux.<p> A solar magnetic sector boundary study from the Jan 1, 2007 Dec 31, 2008 interval showed the occurrence of four or two sectors in a synodic solar rotation cycle. A sector boundary crossing frequently takes place in less than 3 hours. The transition from four sectors to two sectors is surprisingly smooth, in that no interruption in the 27-day synodic period occurs. A superposed epoch analysis of solar wind speed near sector boundary crossings showed a speed minimum about half a day before the crossing, and a maximum about two days after the crossing. The standard deviation reached a minimum at about the same time as the velocity. The sector boundary study also showed that, since Dec. 2007, there were six roughly 27-day synodic solar rotation cycles near spring equinox when away field dominated, and that the following seven 27-day cycles close to the autumnal equinox were dominated by toward field. This is consistent with the quasi-sinusoidal annual magnetic sector polarity oscillations that occur for about three years during solar minimum. These oscillations are due to the mainly dipolar magnetic field which is roughly aligned with the Suns axis, tilted 7.25° from the normal to the ecliptic plane. The three-year oscillation for the present minimum between Solar Cycles 23 and 24 appeared to begin in Dec. 2007. For the past four solar minima, an El Nino event has occurred during the last of the three oscillations, and the El Nino and sinusoidal magnetic oscillation ended together. The new solar cycle began about 6 months before that. During the past eight years, a new 3D topological null-separator formulation of magnetic reconnection and its effect on convection has been led by Dr. M. Watanabe in ISAS at the University of Saskatchewan. This formulation includes two types of interchange reconnection (Russell and Tanaka) as well as the traditional Dungey reconnection. For conditions when the IMF clock angle was within 30° of a Bz+ dominant convection, the new reconnection model shows that the convection can be driven strictly by the two types of interchange reconnection. The model predicts the existence of a reciprocal cell on closed field lines and an interchange merging cell surrounding an interior lobe cell. The construction of the PolarDARN radars at Rankin Inlet and Inuvik, completed in December, 2007, allowed polar cap convection to be measured for predominantly Bz+ conditions. The existence of the two predicted features was confirmed. This also required that satellite data be analyzed to determine the location of the open-closed-field-line-boundary (OCFLB). Several PolarDARN studies are represented to show convection for different IMF clock angles and seasons.

The focus of this thesis is the design, manufacturing and testing of a deployable radio antenna for the ORCASat nanosatellite. First, the context, motivation, requirements, as well as constraints for this project are introduced. Next, a brief overview of theoretical concepts relevant to the contents of this thesis are presented. After the introduction of the relevant background and theory, a literature review is undertaken, and an experiment-based methodology is established. Prior to conceptualizing a new design, detailed consideration is also given to previous attempts at designing a dipole for ORCASat. The root cause of the problems with these attempts is determined experimentally as the presence of ground planes on the circuit board supporting the antenna. After this preliminary investigation, the blocks required for the ORCASat antenna are introduced as the transmission line feeder, the balun, the impedance matching block, and the antenna arm feed. For each of these components, competing design concepts are developed, and the advantages and disadvantages of each of these concepts are presented. After this, the winning design concept is selected and developed into a manufacturable design. This design is identified as a tunable tape spring half wave dipole antenna featuring a specialized feed with electrically and mechanically optimal characteristics, no impedance matching, and a lossy choke balun wound from the coaxial cable feeder, all mounted on a circuit board in a pre-existing Delrin antenna deployer. Next, the manufacturing and assembly of this design is undertaken, followed by the consideration of an informal commissioning procedure. As part of this, a test article consisting of an incomplete prototype of the dipole is tested, and it is shown to have desirable voltage standing wave ratio, input impedance, and return loss characteristics, as well as excellent tunability. Having established that this test article is a good candidate to meet project requirements, it is updated to include as many of the final components of the antenna as possible. Then, formal test procedures for the verification of the tunability, return loss, VSWR, input impedance, antenna pattern, and absolute gain are established, and executed. Based on the results of this formal verification test campaign, it is concluded that the test article meets the requirements presented at the beginning of this thesis, and it is suitable as a radio antenna for the ORCASat mission. After this, the work is concluded by a set of recommendations for future work to prepare the antenna developed in this thesis for flight. / Graduate