1,478 research outputs found

    Electrodynamic Parameters of the Auroral Oval from Combined Spacecraft and Ground Measurements

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    Spacecraft traversing the auroral oval respond primarily to the field-aligned currents at its poleward and equatorward borders that are part of a solenoidal current system. If electric and magnetic field measurements are done, it is possible to determine the integrated Pedersen conductivity of the auroral oval. On the ground, however, one detects primarily the magnetic effects of the Hall currents associated with the auroral oval electric field. If the Hall current can be determined, along with the electric field, one can obtain the Hall conductivity. Inversion of magnetic perturbations in the meridian traversed by the spacecraft can give the Hall current. The Automated Forward Modelling (AFM) method permits this to be done effectively. The method is described with an example based on FAST over the Churchill meridian in Canada. Studying temporal and spatial variations needs multiple instrumented meridians and spacecraft. Efforts to increase the number of instrumented meridians in Canada are described

    Progress on Low-Cost Pulse-Counting Magnetometers for Geomagnetic Studies

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    Poster from American Geophysical Union Fall Meeting 2005, San Francisco"what the world needs now is a good $500 magnetometer

    An Online Mechanics Experiment

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    Physics distance education has grown rapidly in recent years. The theory part of a physics course taught in this way has much common ground with other courses. However, lab instruction is an important part of introductory physics and presents special challenges for distance education. We have developed a prototype introductory mechanics lab which allows many of the instructional features of “on-campus” labs to be presented to students over the internet. These include the ability to control and operate a piece of equipment and to get precision data with included errors, which can be analyzed to give a meaningful result. The lab links theory to practice and allows students to see the principles of mechanics in action

    The Algol Cam: Applied Astronomy Using DSLR Cameras

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    With the refinement in optical technology as of the past few decades, commercial grade cameras have taken a step forward in capabilities. This advancement is the basis for the Algol Cam, a makeshift telescope prototype with a 15 x 10 field of view and the capability to see stars down to 15th magnitude. Combined with Phidgets motors and software programs with functions such as star field analysis and data reduction, the telescope can run surveys for extended periods of time, download photos to a database and compress the data into light curves all automatically. The implications of this project range from numerous astronomy projects to educational and class-based learning tools. *Indicates faculty mento

    A Centenary Survey of Orbits of Co-Orbitals of Jupiter

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    DraftJupiter’s Trojan asteroids fulfill the prediction of Lagrange that orbits can be stable when a small body orbits in specific locations relative to its ‘parent’ planet and the Sun. The first such Trojan asteroid was discovered slightly over one hundred years ago, in 1906, and subsequently similar asteroids have been discovered associated with Mars and with Neptune. To date no Trojans have been discovered associated with Earth, but several horseshoe asteroids, co-orbital asteroids moving along a large range of the Earth’s orbit, have been found. Other planets also are not known to have Trojan-type asteroids associated with them. Since the number of detected Jupiter Trojans has increased dramatically in the last few years, we have conducted a numerical survey of their orbital motions to see whether any in fact move in horseshoe orbits. We find that none do, but we use the enlarged database of information about Trojans to summarize their properties as now known, and compare these to results of theory

    A Survey of Orbits of Co-orbitals of Jupiter

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    working version of a paper planned for Planetary and Space ScienceJupiter’s Trojan asteroids fulfill the prediction of Lagrange that orbits can be stable when a small body orbits in specific locations relative to its ‘parent’ planet and the Sun. The first such Trojan asteroid was discovered in 1906 and subsequently similar asteroids have been discovered associated with Mars and with Neptune. To date no Trojans have been discovered associated with Earth, but several horseshoe asteroids, co-orbital asteroids moving along a large range of the Earth’s orbit, have been found. Other planets also are not known to have Trojan-type asteroids associated with them. Since the number of detected Jupiter Trojans has increased dramatically in the last few years, we have conducted a numerical survey of their orbital motions to see whether any in fact move in horseshoe orbits. We find that none do, although there is some possibility that escaped Trojans have been detected. Here we also use the enlarged database of information about Trojans to summarize their orbital properties as now known

    e Evolution of the Substorm Current Wedge from Ground and Space-based Magnetic Fields

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    As noted in the application, I was also a co-author on several other presentations. The most influential of these was Donovan et al., given orally in the THEMIS session. My own presentation was in the poster session, and thus would be classified as having lesser impact (although 80% of the presentations at this huge (15,000 registrants) conference are posters). Several visitors did come to the poster. Japanese visitors invariably react positively to the fact that well-known senior Japanese scientist Kanji Hayashi is still active and collaborating. Our present main Japanese collaborators were represented by Kaori Sakaguchi and a useful discussion was had about proton aurora. Co-author Christopher Russell from UCLA visited the poster while I was not there and his graduate student will start to work on this event. Collaborator on other projects, Bob McPherron of UCLA, was interested in the subauroral sites mentioned in the poster and we discussed the substorm current wedge that was the main topic. We have followed up on this since and he may be added as a co-author on an article if he agrees sufficiently with our findings. McPherron’s theory of substorms may be contradicted by evidence presented in the poster – thus an interesting exchange of ideas has taken place. This is in the true spirit of scientific investigation. Unfortunately, the poster also drew the attention of Ian Mann of the University of Alberta. This is the only institution in the –world- with which we have a strained relationship. Mann’s comments, which generally had little to do with the poster, are now the subject of follow-up actions yet to be determined. The immediate future work from this poster is an attempt to meet a deadline for the important journal Geophysical Research Letters for its special issue on THEMIS. The immediate thrust has been to implement the IGRF and T89C magnetic models to enable better field-line tracing of the sort presented near the end of the poster. This will allow answering important questions about the mapping of auroras into the magnetosphere by comparing observations on the ground with those at the THEMIS spacecraft in a quantitative way. There have been programming challenges in doing this and it is taking longer than expected. Nevertheless it is still hoped to meet the GRL January 15 deadline. There will also be a special issue of the Journal of Geophysical Research, equally distinguished but with a longer article format, which will allow a more detailed discussion. Donovan will also write up optical results about this event for the two journals, and Igor Voronkov (now working with us at Athabasca University) is writing an article about the theory behind the observations for the GRL special issue. I also attended the THEMIS breakout session on Saturday, Dec. 15 at University of California, Berkeley, am invited to visit UCLA in January for further discussions and work, and expect to attend the next THEMIS Science Team meeting in California in April. Thus, showing the flag and the fact that we are doing meaningful work in support of THEMIS has been a valuable activity, and this poster (part of an evolutionary development in presenting THEMIS-related work) has been an important part of the activity allowing us to participate in THEMIS. Please download PDF file from http://auspace.athabascau.ca:8080/dspace/handle/2149/1386Over the past several years, intensive efforts have resulted in a significant improvement in the ground instrumentation for auroral studies in North America. A major part of this is due to the THEMIS ground program, both in the U.S. and in Canada. The THEMIS Ground-Based Observatory network has fielded 10 additional magnetometers in Canada and Alaska. Further THEMIS magnetometers are part of the GEONS outreach effort, found in the continental U.S. and Alaska. Athabasca University initiatives and collaborations have made yet further magnetometer data available, most notably from a new network of instruments in central Alberta. Several stations of the University of Tokyo STEP network remain operational, and some have been upgraded. There is finally a dense enough set of magnetic data that techniques based on forward modeling, and most relevant to the opportunity afforded by THEMIS, Automated Regional Modeling (ARM), can be reliably used. These techniques specify where net field-aligned current (FAC) and ionospheric electric current flow are located. In some cases the Pedersen system can also be included based on data. Even when it is not, it can be considered collocated with electrojet locations given by ARM. The extension into space of the FAC (net or Pedersen) allows comparison with the perturbations observed at THEMIS. We present results from an event on March 13, 2007, during which THEMIS in its early orbital configuration was over central North America, clear weather prevailed, and a substorm took place whose perturbations were ideally suited for inversion using ARM. At about 5 UT, activations were detected from the ground with magnetic perturbations also detected from THEMIS above the affected stations. The ground perturbations are very well represented by a three-dimensional substorm current wedge (SCW) system, and perturbations in space indicate radial propagation at a time when the electrojet was expanding poleward. Little longitudinal propagation of the SCW is suggested by the ground data.Academic & Professional Development Fund (A&PDF

    Third Coast Percussion presents Points of Contact

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    KSU School of Music presents Third Coast Percussion, Points of Contact.https://digitalcommons.kennesaw.edu/musicprograms/1096/thumbnail.jp

    A One-meter Robotic Telescope for Western Canada

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    Poster presented at CASCA 2008, Victoria1-m class telescopes are arguably the workhorses of modern astronomy and represent an excellent return of science for a relatively modest capital investment. Such instruments can be used in large-field survey work, high precision photometry as well as in providing HQP opportunities for undergraduate and graduate students. Currently there exists a dearth of such instruments in Canada and in the prairie provinces specifically. In this poster we argue for the development of a 1-m, robotic instrument to be situated in western Canada. The proposed instrument will address two central concerns. First, the instrument that we envision will be multi-purpose and through appropriate optical design will function as both a wide field survey instrument and a narrow field instrument capable of high precision photometry. A remote, robotic access telescope will also maximize on-sky efficiency and data output. Second, this telescope will serve as a prototype for a similar remote telescope for the high arctic. Lessons learned in this project should provide valuable insights into many of the issues expected for operation of a remote telescope in the arctic (extreme cold, problems of data transmission etc). We solicit comments and expressions of interest from other researchers who would benefit from such an instrument

    Inner solar system dynamical analogs of plutinos

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    accepted by Icarus, November 2007By studying orbits of asteroids potentially in 3:2 exterior mean motion resonance with Earth, Venus, and Mars, we have found plutino analogs. We identify at least 27 objects in the inner solar system dynamically protected from encounter through this resonance. These are four objects associated with Venus, six with Earth, and seventeen with Mars. Bodies in the 3:2 exterior resonance (including those in the plutino resonance associated with Neptune) orbit the Sun twice for every three orbits of the associated planet, in such a way that with sufficiently low libration amplitude close approaches to the planet are impossible. As many as 15% of Kuiper Belt objects share the 3:2 resonance, but are poorly observed. One of several resonance sweeping mechanisms during planetary migration is likely needed to explain the origin and properties of 3:2 resonant Kuiper Belt objects. Such a mechanism likely did not operate in the inner solar system. We suggest that scattering by the next planet out allows entry to, and exit from, 3:2 resonance for objects associated with Venus or Earth. 3:2 resonators of Mars, on the other hand, do not cross the paths of other planets, and have a long lifetime. There may exist some objects trapped in the 3:2 Mars resonance which are primordial, with our tests on the most promising objects known to date indicating lifetimes of at least tens of millions of years. Identifying 3:2 resonant systems in the inner Solar System permits this resonance to be studied on shorter timescales and with better determined orbits than has been possible to date, and introduces new mechanisms for entry into the resonant configuration
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