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The Expanded Owens Valley Solar Array (EOVSA) is a major expansion of our older array, and was funded by NSF using American Recovery and Reinvestment Act (ARRA) funds. The project expanded the array from its old complement of 7 antennas to a total of 15 by adding 8 new antennas, and replaced the control systems, wiring, and signal processing of the pre-existing antennas with modern, far more capable and reliable systems based on newly developing technology. In so doing, we have created a university-led community facility that addresses a broad range of new science to serve the scientific community. The project aims to support that community by providing open data access and software tools for analysis of the data, to exploit synergies with on-going solar research in other wavelength bands. EOVSA is a world-class facility for scientific research at microwave radio frequencies (1-18 GHz) in areas of important national interest, such as understanding the Sun's influence on the Earth and near-Earth space environment—a subject broadly termed Space Weather. The solar science being addressed focuses on the magnetic structure of the solar corona, on transient phenomena resulting from magnetic interactions, including the sudden release of energy in solar flares, and subsequent particle acceleration and heating, and on space weather phenomena. The project wasl be completed in early 2017, and has been providing solar-dedicated observations ever since.

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The range of science to be conducted with the Expanded OVSA is broad and unique. Check out the science page for more on each topic.

  • Magnetic and Plasma Structure Above Active Regions
    • Coronal Magnetography
    • Temperature, Density, Nonthermal Electrons
  • Flaring Loops and Particle Acceleration in Solar Flares
    • Electrons and Magnetic Fields in Flaring Loops
    • Dynamic Imaging and Turbulence
  • Drivers of Space Weather
    • F10.7 Images
    • Eruptive Events
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The OVSA Expansion was a complete redesign of the array that added 8 new 2-m antennas, and moved the 5 pre-existing 2-m antennas to new locations. These 13 antennas provide 78 baselines for imaging. A 27-m antenna was completely refurbished and modernized with a new control system and a cooled receiver, for dedicated calibration of the array. The maximum baseline grew to more than 1.5 km, for a typical resolution (varies by time of day and season) of about 60"/n GHz. The table at right summarizes the instrument parameters. Below are some highlights of the instrument specifications. These are subject to change as the design becomes more detailed during development.

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OVSA Expansion Project Instrument

OVSA Upgrade Specifications

Frequency range

1 – 18 GHz

Number of data channels

2 (dual polarization)

IF bandwidth

500 MHz per channel

Frequency resolution

Raw: 122 kHz (4096
spectral channels)
Science: <40 MHz

Time resolution

Sample time: 20 ms
Full Sweep: 1 s

Polarization

Full Stokes (IQUV)

Number correlator inputs per data channel

16

Number and type of antennas

Five 2-m equatorial
Eight 2-m azel
A 27-m equatorial (cal. only)

Angular resolution

57"/ n GHz × 51"/ n GHz

Array size

1.08 km EW x 1.22 km NS

 


This material is based upon work supported by the National Science Foundation under Grant Nos. AST-1615807. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. Funding is also provided by a NASA Supporting Research & Technology grant NNX14AK66G.