Focal Plane Instrumentation at Big Bear Solar Observatory Wenda Cao Big Bear Solar Observatory New Jersey Institute of Technology

Why ? How are magnetic fields generated and how are they destroyed? What role do magnetic fields play in the organization of plasma structures and the impulsive releases of energy? What are the mechanisms responsible for solar variability (that ultimately affects the Earth)? NST NST NST An angular resolution of 0.1 arcsec or better to resolve the pressure scale height and the photon mean free path A high photon flux at the critical spatial resolution for precise magnetic and velocity field measurements Access to a broad set of diagnostics, VIR to IR NST Why ? 2 Nov 2007

What ? An angular resolution of 0.1 arcsec or better to resolve the pressure scale height and the photon mean free path A high photon flux at the critical spatial resolution for precise magnetic and velocity field measurements Access to a broad set of diagnostics, VIR to IR Adaptive Optics: diffraction limited image; InfraRed Imaging Magnetograph (IRIM): infrared high precision polarimetry and spectrometry; Visible Imaging Magnetograph (VIM): visible spectrometry and polarimetry; Real-time Speckle Image Processor: high resolution dynamics monitor; What ? 2 Nov 2007

Where ? Adaptive Optics 2 Nov 2007

Adaptive Optics System Tutelary to Obtain High Spatial Resolution 2 Nov 2007

Principle of Adaptive Optics How ? Principle of Adaptive Optics 2 Nov 2007

Scientific Results Adaptive Optics 2 Nov 2007 System Feature Corrected modes 35 Subapertures 76 Actuators 97 Bandwidth (closed-loop) 120 Hz Residual wave front error 1.9 rad2 (AO off) Mean squared wave front error 0.58 rad2 (AO on) Wavelength range for WFS Broadband visible Intensity contrast (lock point) ~ 0.65 @ 550 nm Light fraction (WFS) ~ 5 % Adaptive Optics 2 Nov 2007

InfraRed Imaging Magnetograph Infrared Imaging Magnetograph -- IRIM 2 Nov 2007

Infrared Imaging Magnetograph – IRIM How ? Wavelength Range: 1 ~ 1.6 m ( Fe I 1.5648 m and Fe I 1.5651 m ) Field of View: ~ 80” × 80” Four Operation Modes: ► Polarimetry: Stokes I, Q, U, V ► Spectrometry: spectral line profile ► Dopplergram: a few selected spectral points ► Photometry: narrow (~0.1Å), medium(~2.5Å), broad(~50Å) High Spatial Resolution: close to diffraction limit High Temporal Resolution: < 1 min Moderate Spectral Resolution: λ/δλ~ 105 High Throughput: > 35 % for polarized light High Zeeman Sensitivity: V / I ~ 10-4 λ X Y Infrared Imaging Magnetograph – IRIM 2 Nov 2007

Infrared Imaging Magnetograph – IRIM How? IRIM = Fabry-Perot + Birefringent Lyot Filter + Interference Filter Infrared Imaging Magnetograph – IRIM 2 Nov 2007

Observation I – IRIM Polarimetry IRIM and MDI: Observation I – IRIM Polarimetry 2 Nov 2007

Visible Imaging Magnetograph Visible Imaging Magnetograph -- VIM 2 Nov 2007

How ? Wavelength Range: 400 ~ 700 nm ( G-band, Fe I 630.2 nm and H 656.3 nm) Field of View: ~ 80” × 80” Four Operation Modes: ► Polarimetry: Stokes I, Q, U, V ► Spectrometry: spectral line profile ► Dopplergram: a few selected spectral points ► Photometry: narrow (~0.08Å) High Spatial Resolution High Temporal Resolution: < 1 min Moderate Spectral Resolution: λ/δλ~ 105 High Throughput: > 65 % λ X Y VIM 2 Nov 2007

Observation II – IRIM Photometry 2 Nov 2007

The future of BBSO focal plane instrument Next … Adaptive Optics: AO-76 transfer to NST NST high order AO system MCAO Infrared Imaging Magnetograph: Upgrade to NST Dual Infrared Fabry-Perot System Visible Imaging Magnetograph: Real-time Speckle Processor: Phase Diversity Processor The future of BBSO focal plane instrument 2 Nov 2007