Development of an Advanced Space Weather Warning System: The PreSTIM Laboratory Prototype, 15-R9557Printer Friendly Version
Inclusive Dates: 07/01/05 Current
Background - Explosions coronal mass ejections and flares on the surface of the sun can release large amounts of energy and mass into the interplanetary medium. A fraction of these perturbations will inevitably impact directly on the Earth's magnetosphere. Geospace, the region surrounding our planet with a magnetosphere, is a protective environment that shields the upper atmosphere and low-Earth orbit against the solar wind and energetic particles. Under solar storm conditions, when transient solar activity impacts and transforms the magnetic bubble, the reaction of the Earth's environment is, at times, violent and dangerous. Changing magnetic fields induce currents, and this is also true for the ionosphere (the uppermost layer of the Earth's atmosphere). These currents can interfere with human technology on the Earth's surface and in space. Mainly, the positions of the radiation belts, carefully avoided by human space mission planners, become uncertain and often suddenly interfere with human presence in space. Severe radiation damage to humans and their support systems can result and needs to be avoided. Such severe space weather conditions can only now be forecast well in advance, with the Pre-Shock Suprathermal Ion Monitor (PreSTIM) placed on upcoming space weather monitoring missions. In this research project, we want to bring PreSTIM from the concept level to a fully functional laboratory prototype. The development of the PreSTIM is done in collaboration with the Applied Physics Laboratory (APL) at Johns Hopkins University.
The traditional way to derive kinetic energy (E), mass (m) and charge (q) is to determine the mass-per-charge by selecting a certain E/q, the TOF of the particle over a known distance, and the total kinetic energy with a solid-state detector. The PreSTIM concept of measuring suprathermal ions is entirely new. We use the stopping power of two carbon foils in combination with a newly designed ion optics aperture to separate ion species and determine individual fluxes. The sophisticated ion optics configuration separates ions in energy-per-charge so that they are ordered when they enter the TOF section with nearly parallel paths. Knowing the energy loss of the particle in the carbon foils, we can derive the kinetic energy, the mass, and the charge of the particle.
Approach - To achieve our goal, we divided the project in four objectives:
Accomplishments - We created a three-dimensional electro-optics model for the laboratory prototype. We used the model to test different design options to determine the optimum configuration within our parameter space. We optimized the electro-optics of both the ESA and the TOF section. We have started the mechanical design of our laboratory prototype in parallel. The ESA is about to be tested in our vacuum chamber with ion beams. PreSTIM is a sensor that improves the capabilities for forecasting interplanetary shocks at Earth. A previous study with data from the STICS experiment on the Wind spacecraft showed that suprathermal foreshock ions provide early warning for incoming shocks. However, this study was limited to data obtained during the rising phase of the solar cycle. We have extended this analysis using the WIND/STICS dataset and demonstrated that measurements from instruments like PreSTIM will serve as an excellent Space Weather Monitor and will accurately forecast the arrival of upcoming space storms during other phases of the solar cycle as well.