Expanded Owens Valley Solar Array

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EOVSA (Expanded Owens Valley Solar Array) is a solar-dedicated radio interferometer operated by the New Jersey Institute of Technology and serving as a National Science Foundation Geospace Facility. NSF.jpg

Operation of EOVSA is supported by the National Science Foundation under Grant No. AGS-2130832. 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. 

This wiki serves as the site for EOVSA documentation.


OVRO-LWA (Owens Valley Radio Observatory Long Wavelength Array) is an all-sky imager that has a new solar-dedicated spectroscopic imaging mode. OVRO-LWA is a multi-institutional collaboration led by Caltech. NJIT Solar Radio Group is leading its solar-mode development and science. At the bottom of this page are new links for that facility.

EOVSA Documentation

Using EOVSA Data

System Software

EOVSA Observing Log

2016 November; December

2017 January; February; March; April; May; June; July; August; September; October; November; December

2018 January; February; March; April; May; June; July; August; September; October; November; December

2019 January; February; March; April; May; June; July; August; September; October; November; December

2020 January; February; March; April; May; June; July; August; September; October; November; December

2021 January; February; March; April; May; June; July; August; September; October; November; December

2022 SQL Outage

2023 January; February; March; April; May; June; July; August; September; October; November; December

2024 January; February;


Trouble Shooting Guide

Tohban Records

Owen's Notes

Caius' Notes

Tohban EOVSA Imaging Tutorial A-Z

Tohban OVRO-LWA Imaging Tutorial

Tohban Guide to Self Calibration and Imaging for EOVSA

Guide to Upgrade SolarSoft(SSW)

EOVSA Flare List

See this link for a list of EOVSA flares as a Google Spreadsheet.

Recent Flare List (2021-)

An older link is available at the EOVSA website.

EOVSA Publications

Here is a (partial) list of publications that utilize EOVSA data. See also the collection of EOVSA publications at this NASA/ADS Library.

Mondal, S., Chen, B. & Yu, S. (2023) ApJ, submitted Multifrequency microwave imaging of weak transients from the quiet solar corona
Lörinčík et al (2022) Frontiers, 9, 1 Rapid variations of Si IV spectra in a flare observed by interface region imaging spectrograph at a sub-second cadence
Kou et al. (2022) Nature Communications 13, 7680 Microwave imaging of quasi-periodic pulsations at flare current sheet
Fleishman et al. (2022) Nature 606, 674 Solar flare accelerates nearly all electrons in a large coronal volume
Li, X., et al., (2022) ApJ, 932, 92 Modeling Electron Acceleration and Transport in the Early Impulsive Phase of the 2017 September 10th Solar Flare
Liu, N., et al., (2022), ApJ, 930, 154 Multi-instrument Comparative Study of Temperature, Number Density, and Emission Measure during the Precursor Phase of a Solar Flare
Zhang et al. (2022), ApJ, 932, 53 Implications for additional plasma heating driving the extreme-ultraviolet late phase of a solar flare with microwave imaging spectroscopy
Lopez et al. (2021), A&A, 657, A51 A solar flare driven by thermal conduction observed in mid-infrared
Wei et al. (2021), ApJ, 923, 213 Coronal Magnetic Field Measurements along a Partially Erupting Filament in a Solar Flare
Shaik & Gary (2021), ApJ, 919, 44 Implications of Flat Optically Thick Microwave Spectra in Solar Flares for Source Size and Morphology
Kocharov et al. (2021), ApJ, 915, 12 Multiple Sources of Solar High-energy Protons
Chen et al. (2021), ApJL, 908, L55 Energetic Electron Distribution of the Coronal Acceleration Region: First results from Joint Microwave and Hard X-ray Imaging Spectroscopy
Chhabra et al. (2021), ApJ, 906, 132 Imaging Spectroscopy of CME-Associated Solar Radio Bursts
Reeves et al. (2020), ApJ, 905, 165 Hot Plasma Flows and Oscillations in the Loop-top Region During the September 10 2017 X8.2 Solar Flare
Yu et al. (2020), ApJ, 900, 17 Magnetic Reconnection During the Post Impulsive Phase of the X8.2 Solar Flare: Bi-Directional Outflows as a Cause of Microwave and X-ray Bursts
Chen et al. (2020b), Nature Astronomy, 4, 1140 Measurement of magnetic field and relativistic electrons along a solar flare current sheet
Chen et al. (2020a), ApJL, 895, 50 Microwave Spectral Imaging of an Erupting Magnetic Flux Rope: Implications for the Standard Solar Flare Model in Three Dimensions
Kuroda et al. (2020), Frontiers, 7, 22 Evolution of Flare-accelerated Electrons Quantified by Spatially Resolved Analysis
Glesener et al. (2020), ApJL, 891, 34 Accelerated Electrons Observed Down to <7 keV in a NuSTAR Solar Microflare
Karlicky at al. (2020), ApJ, 889, 72 Drifting Pulsation Structure at the Very Beginning of the 2017 September 10 Limb Flare
Fleishman et al. (2020), Science, 367, 278 Decay of the coronal magnetic field can release sufficient energy to power a solar flare
Gary et al. (2020), BAAS 52, 385.01 Direct link to AAS iPoster A new view of the solar atmosphere: daily full-disk multifrequency radio images from EOVSA
Polito et al. (2018), ApJ, 864, 63 Broad Non-Gaussian Fe XXIV Line Profiles in the Impulsive Phase of the 2017 September 10 X8.3-class Flare Observed by Hinode/EIS
Gary et al. (2018), ApJ, 863, 83 Microwave and Hard X-Ray Observations of the 2017 September 10 Solar Limb Flare
Kuroda et al. (2018), ApJ, 852, 32 Three-dimensional Forward-fit Modeling of the Hard X-ray and the Microwave Emissions of the 2015 June 22 M6.5 flare
Wang et al. (2017), Nature Astronomy, 1, 85 High-resolution observations of flare precursors in the low solar atmosphere
Nita et al. (2016), J. Astron. Instr., 5, 1641009-7366 EOVSA Implementation of a Spectral Kurtosis Correlator for Transient Detection and Classification

VLA Flare List and Publications

See this link for a list of flare observations made by the Karl G. Jansky Very Large Array (VLA). Below is a partial list of publications that utilize VLA solar data (see also this NASA/ADS Library).

Radio Data from Around The Heliosphere

OVRO-LWA Solar-Dedicated Spectroscopic Imager

The OVRO-LWA (Owens Valley Radio Observatory Long Wavelength Array) has recently been upgraded to include a solar-dedicated beam and two solar imaging modes (slow visibilities of 352 antennas with a 10-s cadence, and fast visibilities of 48 antennas with a 0.1-s cadence). The large collecting area and excellent calibration provide unprecedented high-sensitivity imaging of the quiet Sun and bursts. The array is currently in commissioning and observations are not yet continuous, but they are becoming more so. See the daily realtime data at http://ovsa.njit.edu/status.php for real-time display of the spectrogram and a selection of images, both updated on a 1-min cadence.

Solar-Dedicated Modes


The beamformer uses the 256 core antennas to form a synthesized beam of more than 1 degree in size that tracks the Sun from sunrise to sunset. This permits a continuous record of the full-Stokes total flux (without spatial resolution) of the Sun (a dynamic spectrum) with 24 kHz frequency resolution (3072 frequencies from 15-90 MHz) and as low as 1 ms time resolution.

Slow Visibility Imaging

In this mode, the entire 352-element array is interferometrically correlated to provide visibilities for imaging at all 3072 frequencies at 10-s time resolution. This is ideal for imaging quiet Sun and slowly-varying emission such as coronal mass ejections and active region variability.

Fast Visibility Imaging

In this mode, a subset of 48 antennas (chosen to include mainly outer antennas to maintain good spatial resolution) is interferometrically correlated to provide visibilities for imaging at 768 frequencies (96 kHz frequency resolution) at 0.1-s time resolution. This is ideal for imaging rapidly varying emission such as type II and type III bursts as well as many other solar spectral fine structures.

Inital Data Access

In its current commissioning state, we try to run the beamformer and imaging pipeline every day in real-time since November 2023 (no latency for beamforming spectrograms and 5-10 min latency for images). Quicklook real-time spectrograms/images can be accessed from http://ovsa.njit.edu/status.php. To access data from previous days, use the following links (replace yyyymmdd with the date you desire):

Note our pipeline processing development is still in the early phase. For example, absolute flux calibrations have not been done for the beamformer spectrograms. Also, artificial effects (including ionospheric refraction effects) are present in the images that cause distortions/shifts. We caution interested users only to consider them for quick-look purposes at this point. Please contact the EOVSA PIs (Dale Gary, Bin Chen) if you intend to use them for science.

OVRO-LWA Observing Log

Link to the OVRO-LWA solar observing logs (in Google Doc)