SH31B-01 INVITED 08:10h
DASI: Distributed Arrays of Small Instruments
The NAS Solar and Space Physics Decadal Survey has recommended that the next major ground-based instrumentation initiative for space science research be the deployment of widely-distributed arrays of small instrumentation. Such arrays will provide continuous real-time observations of Earthspace with the resolution needed resolve mesoscale phenomena and their dynamic evolution. Ground-based arrays will address the need for observations to support the next generation of space weather data-assimilation models and will push our understanding of the physical processes which interconnect the spheres of Earthspace to a new level. It is envisioned that DASI instrumentation will provide real-time data for a wide variety of research, applications, and educational users. Infrastructure issues including instrument design and deployment, communications, and data distribution will be important aspects of a DASI plan. In order to provide a strong foundation for future initiatives addressing the DASI goals, the NAS Committee on Solar and Space Physics (CSSP) has undertaken a study of the scientific need for such arrays, the infrastructure needed to support and utilize them, and an implementation plan for their deployment. Community input was solicited in the spring of 2004 and a working group meeting was held at the NAS Woods Hole facilities in June, 2004 to discuss a science plan for DASI and to address issues for inclusion in a DASI report. The focus of the CSSP report is the compelling science which will be enabled by the development of arrays of small instruments. The current status and an outline of the DASI science report will be reviewed.
SH31B-02 08:30h
Autonomous Antarctic Magnetometer Arrays to Support ICESTAR (Interhemispheric Conjugacy Effects in Solar - Terrestrial and Aeronomy Research)
ICESTAR is a new SCAR (Scientific Committee for Antarctic Research) initiative striving for international coordination of interhemispheric research in the areas of solar-terrestrial physics and polar aeronomy, promoting exchange of research ideas, and sharing experimental data from various arrays of geophysical instruments deployed over the polar regions. A specific need for the ICESTAR program is additional high resolution autonomous magnetometer stations on the Antarctic Plateau to provide a dense two-dimensional array of stations conjugate to the station arrays in Greenland. The new stations would extend the existing British Antarctic Survey low power magnetometer array poleward and eastward. The new stations will utilize a low-noise, high resolution magnetometer to obtain 1-second data thus enabling magnetic pulsation investigations. An additional important design criteria is the need for near real time data access and this will be achieved using IRIDIUM satellite data acquisition. We present our design for the next generation Antarctic autonomous magnetometer station, deployment considerations, and a brief overview of ICESTAR scientific plans.
SH31B-03 08:45h
The Mileura Widefield Array: Application To Heliospheric Observations and Space Weather
Radio arrays with hundreds of distributed antenna elements have recently become possible due to advances in digital information technology including high speed signal processing and wideband data transport. This paper presents the design of an array operating at frequencies below 300 MHz whose goal is to improve the sensitivity and resolution of astronomical and heliospheric observations. A demonstrator system for this array is now being planned for deployment at the Mileura Station in Western Australia, where the RFI environment is ideally suited for such low frequency observations. The potential of such an array for heliospheric and space weather observations has been studied using two techniques, namely interplanetary scintillations and Faraday rotation. Both techniques depend on observing the emission from astronomical radio sources as they are occulted by a coronal mass ejection traveling in the solar wind. The measurements will allow a determination of the density and velocity of the CME, as well as its magnetic field strength and orientation. In addition, the array can be used to measure variations in the Earth's ionosphere on very small scales within the field-of-view. This paper summarizes the array design and capabilities, outlines the planned demonstrator system at Mileura, and illustrates the expected heliospheric observations using simulations of recent space weather events.
http://web.haystack.mit.edu/MWA
SH31B-04 09:00h
Magnetic Field Measurements from The Coronal Multi-Channel Polarimeter
We have constrcted a filter-based polarimeter optimized for the measurement of magnetic fileds in the solar corona. The instrument will observe the coronal emission lines of FeXIII at 1074.7 and 1079.8 nm as well as the chromospheric HeI emission line at 1083 nm. The instrument consists of a polarimeter allowing complete Stokes I,Q,U,V measurement followed by a Lyot birefringent filter with dual passbands of 0.14 nm width. Both the polarimeter and filter employ liquid crystals for rapid electro-optical tuning. Measurement of the longitudinal Zeeman effect provides information on the strength of the line-of-sight component of the magnetic field while the observation of resonance scattering will constrain the plane-of-sky field direction. Precise measurement of plasma velocity is also possible. Such measurements are critical for addressing many outstanding problems in coronal physics. This instrument was deployed to the 20-cm One Shot coronagraph at NSO's Sacramento Peak Observatory in January of 2004. Observations were obtained during observing runs in March, May and August of 2004. Results from these observing runs will be presented.
SH31B-05 09:15h
An Imaging Spectrograph for Ground Based, Round-the-Clock Optical Aeronomy Studies
In recent years we have developed a high resolution imaging spectrograph at Boston University that is capable of unambiguously measuring faint airglow/auroral emissions buried in the bright solar background continuum of the daytime (solar zenith angle $<$ 90 deg) sky. Two versions of this instrument have been developed. A multi-wavelength implementation, called High Throughput Imaging Echelle Spectrograph (HiTIES), has been used to simultaneously measure several twilighttime/nighttime optical emissions located anywhere in the visible range at moderate (0.03 nm) resolution, while the High Resolution Imaging Spectrograph using Echelle grating (HIRISE) has been used to study daytime airglow and auroral emissions at higher (0.01 nm) resolution. Both of these rugged instruments have been deployed at Boston University as well as other sites (Sondre Stromfjord, Carmen Alto and Svaalbard) without any technical difficulties. They have been used to investigate such wide-ranging aeronomy problems as 630.0nm dayglow, forecasting of Equatorial Spread F development, sunlit cusp as well as the daytime aurora over Boston on October 30, 2003. These proof-of-concept experiments have demonstrated the value of this new tool for future studies of the dynamical processes in space physics and aeronomy. We are presently incorporating improved capabilities and have plans to deploy more than one spectrograph simultaneously for tomographic applications. In this paper we will review the scientific contributions we have made with these two instruments, our future plans and outline their possible role in the International Heliophysical Year.
SH31B-06 09:30h
An All-Sky Imaging Poly-Etalon Fabry-Perot System to Observe 630nm Oxygen Emissions: Preliminary Observations and Calibrations from Millstone Hill.
An all-sky triple Fabry-Perot system with a theoretical spectral resolution of 1.7pm and a Free Spectral Range of 0.39nm, designed for measurements of oxygen emission, has been built and assembled at the Haystack observatory in Millstone Hill. The all-sky imaging poly-etalon Fabry-Perot system is used to monitor thermospheric dynamics and temperatures at the Millstone Hill Aeronomical Observatory. Oxygen 630.0nm emission is monitored to determine thermospheric vector wind velocities simultaneously in multiple wedges over a 120 degree field of view from measurement of the Doppler shift of the emission line. Line width is used to determine thermospheric temperatures at 300 Km. Maps of all-sky wind velocity and temperatures are presented. The challenge of making a similar measurement during the day lies in the ability to separate the weak 630.0nm dayglow emission (1.5 kiloRayleigh) from the very brighter scattered solar component (50000 kiloRayleigh/nm). A high spectral resolution Fabry-Perot system is required to reject a good fraction of the unwanted background. Presented here will be a comparison of modeled instrument performance to preliminary daytime calibrations of the instrument. This instrument is to be deployed in the Scientific Solutions airglow observatory at the Cerro Tololo observatory (30.17S 70.81W) in Chile. Post deployment observation will be made in conjunction with two other Clemson University Fabry-Perots in Peru creating a longitudinal chain of interferometers for thermospheric observations. These instruments will make autonomous day and nighttime observations of thermospheric dynamics. Instruments of this type can be constructed for a global chain of autonomous airglow observatories.
http://www.sci-sol.com
SH31B-07 09:45h
Ground-Based Cosmic Ray Detectors for Solar-Terrestrial Research and Space Weather Forecasting
Owing to the large detector mass required to detect high-energy cosmic rays, ground-based instruments remain the state-of-the-art method for studying these elusive particles. Neutron monitors and muon detectors record the byproducts of nuclear interactions of high-energy primary cosmic rays with Earth's atmosphere. At energies up to $\sim$100 GeV, primary Galactic cosmic rays experience significant modulation in response to the magnetic field of the solar wind. With suitable analysis, ground-based observations yield unique information on the large-scale magnetic structure of passing solar wind disturbances. Cosmic rays also carry precursory signatures of approaching disturbances (such as major CMEs) that are useful for space weather forecasting. We discuss the current status of neutron monitor and muon detector arrays, what can be gained by better coordination of existing arrays, and what might be gained through expansion of the existing network. Supported by NSF grants ATM-0000315 and ATM-0207196.
http://www.bartol.udel.edu/~NeutronM/