The Helioseismic & Magnetic Imager on the Solar Dynamics Observatory. The HMI Team – Stanford University, LMSAL, HAO, ++. HMI Data Processing. Data Product. HMI Data. Internal rotation Ω(r,Θ) (0<r<R). Spherical Harmonic Time series To l =1000. Heliographic Doppler velocity maps.
TheHelioseismic & Magnetic Imageron theSolar Dynamics Observatory
The HMI Team – Stanford University, LMSAL, HAO, ++
HMI Data Processing
Internal rotation Ω(r,Θ)
Internal sound speed,
Full-disk velocity, v(r,Θ,Φ),
And sound speed, cs(r,Θ,Φ),
Carrington synoptic v and cs
Wave travel times
High-resolution v and cs
HMI Major Science Objectives
Deep-focus v and cs
Far-side activity index
Magnetic Field Maps
Solar wind models
Solar limb parameters
HMI Data Analysis Pipeline
HMI/AIA JSOC(Joint Science & Operations Center)
The HMI instrument design and observing strategy are based on the highly successful MDI instrument, with several important improvements. HMI observes the full solar disk in the Fe I absorption line at 6173Å with a resolution of 1 arc-second. HMI consists of a refracting telescope, a polarization selector, an image stabilization system, a narrow band tunable filter and two 4096² pixel CCD cameras with mechanical shutters and control electronics. The continuous data rate is 55Mbits/s.
The polarization selector, a set of rotating waveplates, enables measurement of Stokes I, Q, U and V with high polarimetric efficiency. The tunable filter, a Lyot filter with one tunable element and two tunable Michelson interferometers, has a tuning range of 600 mÅ and a FWHM filter profile of 76 mÅ.
Images are made in a sequence of tuning and polarizations at a 4-second cadence for each camera. One camera is dedicated to a 45s Doppler and line-of-sight field sequence while the other to a 90s vector field sequence. All of the images are downlinked for processing at the HMI/AIA Joint Science Operations Center at Stanford University.
Fold Mirror Assembly
BDS Beam-splitter Assembly
Filter Oven Assembly
Lyot Filter Assembly
Oven Controller E-Box
ISS Mirror Assembly
Hollow Core Motors
Secondary Lens Assembly
Focal Plane Assembly
ISS Beam-splitter Assembly
Limb Sensor Assembly
ISS Pre-Amp Electronics Box
Camera Electronics Box
Primary Lens Assembly
Front Window Assembly
Front Door Assembly
HMI Principal Optics Package Components
Box: 0.84 × 0.55 × 0.16 m
Over All: 1.19 × 0.83 × 0.30 m
Mass: 44.0 kg
First Mode: 73 Hz
Effective Focal Length: 495 cm
Telescope Clear Aperture: 14 cm
The solid lines show the HMI filter transmission profiles at 76 mÅ spacing. The black dashed line is the profile used for the continuum filtergram. The dotted line shows the Fe I line profile.
HMI – AIA Joint Science Operations (JSOC-SDP)
Science Data Processingfor theSolar Dynamics Observatory
The JSOC-SDP Team – Stanford University
The JSOC consists of three components: The IOC (Instrument Operations Center) at LMSAL performs instrument operations for both HMI and AIA; The SDP (Science Data Processing) facility at Stanford handles data for both HMI and AIA by receiving it from the SDO ground system, short term and long term archive, processing to “level-1” products for both instruments, higher level processing for HMI and data access and export for both instruments; The AVC (AIA Visualization Center) provides tools for interactive inspection and analysis of AIA images and HMI magnetic data.
Products from Level-1 and above are served through the open server at the JSOC web site. The higher level products are in development and are expected to become available over the coming months.
HMI Data Products and Access
All HMI data is available. Science level data products are being placed on an open web server with a lag of a day or so of time of observation.
Lower level and intermediate products are available on request.
The data volume is large, more than a terabyte per day. Thus we encourage users to export only the data they actually need for immediate analysis. We are committed to provide tools to allow subsetting of the data and of providing multiple access tools appropriate for different data volumes for different users.
Contributors to the HMI development up through launch include: