Early Magnetic Field
Observations From HMI
J. Todd Hoeksema and the HMI Magnetic Field Team:
Yang Liu, Keiji Hayashi, Xudong Sun, Jesper Schou,
Sebastien Couvidat, Xuepu Zhao, Rick Bogart, Priya Desai
Steve Tomczyk, Juan Borrero, Rebecca Centeno Elliot
K.D. Leka, Graham Barnes, Ashley Crouch
M Turmon, P Schuck, T. Wiegelmann
The rest of the HMI Team
Stanford, HAO, CORA, JPL, GSFC, MPS
HMI 2010.05.20_19:19:30
Early HMI Magnetic Field Observations
Abstract
HMI, the Helioseismic and Magnetic Imager
on SDO is producing a synoptic series of
full-disk arc-second magnetograms.
Longitudinal field is determined every 45s
and vector inversions computed every 12
minutes in patches.
Higher level products will be produced
including tracked AR patches, synchronic
frames, NLFFF and MHD coronal field
models, and photospheric flow maps
Some quick-look products are available in
minutes for space weather purposes.
Early HMI Magnetic Field Observations
HMI Magnetic Field Observables
• Line-of-sight magnetic field is computed from
Doppler velocity in two polarizations, as for MDI.
• Vector Field is computed from Stokes
parameters derived from an independent set of
polarized filtergrams.
• The possibility of combining the two cameras is
being explored to improve sensitivity.
• The nominal line-of-sight cadence is 45
seconds. The basic vector field cadence is 90s
or 135 seconds.
Early HMI Magnetic Field Observations
HMI Magnetic Field Observables
• Vector field data products are the following
quantities, uncertainties on each, and
some covariances:
– |B| - total flux
– Filling factor (where possible)
– Inclination (gamma) to the line of sight
– Azimuth (phi) CCW relative to ‘up’ on the
CCD camera
– Magnetic line-of sight velocity
• Data will be exported in a variety of
coordinate systems: [Bx,By,Bz],
[B_total,gamma,phi], and [Br,Btheta,Bphi]
Early HMI Magnetic Field Observations
Magnetic Processing Scheduling
There are four schedules for Magnetic Field data processing
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Quick Look/Near Real Time
– Routine processing of some data available within minutes of
observation
•
Standard
– Routinely completed for all data on regular cadence (e.g.
Vector B) after about 25 hours.
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On Demand
– Completed for small fraction of data when interesting things
happen or whenever requested by a qualified user (HiRes
MHD time series for a big flare & CME campaign
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On Request
– Products, such as high-resolution time series of MHD model
solutions, will be generated as resources allow. Completed
when system resources allow
Early HMI Magnetic Field Observations
Definitive Science Observables – HMI Magnetic Field Images
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Standard Pipeline Observables
– 45-second
• Magnetic line-of-sight field on full disk
• Continuum intensity and line depth on full disk
• Doppler velocity on full disk
– 12-minute
• Inverted vector B on full disk
• Disambiguated B on selected patches
• IQUV
– 12-hour
• Disambiguated vector field on full disk
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On Demand
– 180-second spatially binned disambiguated vector field in patches
– 360-second disambiguated patches
– 12-minute full disk disambiguated vector field
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On Request
– 90-second disambiguated patches
– 90-second or other cadence IQUV
– Anything else
Early HMI Magnetic Field Observations
HMI 720s Magnetogram
Early HMI Magnetic Field Observations
Early HMI Magnetic Field Observations
Magnetic Field Blos Zero Level
• x
45s
720s
Early HMI Magnetic Field Observations
Magnetic Field Blos Mean Field
HMI – MDI – WSO
Early HMI Magnetic Field Observations
HMI Blos 45 vs
HMI Blos Vector
HMI Blos 45 vs
HMI Blos 720
Early HMI Magnetic Field Observations
HMI Blos
Vector Method
HMI Blos 45 vs
HMI Blos 720
Early HMI Magnetic Field Observations
HMI vs MDI Blos Comparison
Early HMI Magnetic Field Observations
HMI vs MDI Blos Comparison
Early HMI Magnetic Field Observations
MDI vs Solis
MDI vs MtWSO
HMI vs MDI
HMI = 1.03 SOLIS
Early HMI Magnetic Field Observations
AR 11066
Early HMI Magnetic Field Observations
AR 11069
Early HMI Magnetic Field Observations
HMI Vector Inversion and MDI FD LoS Comparison
R. Centeno Eliot, J. Borrero, S. Tomczyk, K. Hayashi, Y. Liu
Early HMI Magnetic Field Observations
Frame of Vector Field Movie from Mar 29 Sunspot
K. Hayashi, R. Centeno Eliot, et al.
Early HMI Magnetic Field Observations
Frame of Vector Field Movie from May 22 Sunspot
K. Hayashi, R. Centeno Eliot, et al.
Early HMI Magnetic Field Observations
Additional Magnetic Field Model Products
Produced as Standard ,On-demand, or On-request
• Synoptic synchronic maps and frames
• Automated Identification and Tracking of AR Patches
and other features – 12 minutes
• PFSS Model – Various resolutions and Cadences
• Open Field Foot Point Maps
• NLFFF Model – AR patches, daily and on request
• MHD Models
– Daily low-resolution
– Monthly and major events in hi-res
• Surface Flow Maps
– ILCT, FLCT DAVE4VM
Early HMI Magnetic Field Observations
CR2096 HMI LoS Synoptic Map – Y. Liu & X. Zhao
Early HMI Magnetic Field Observations
CR2096 HMI Synoptic Map Closeup – Y. Liu & X. Zhao
Early HMI Magnetic Field Observations
MDI
Feb 9, 2002
AR Patch ID
Mike Turmon & Xudong Sun
HMI
March 29, 2010
Early HMI Magnetic Field Observations
DAVE4VM Result Showing Horizontal Velocity
Pete Schuck, Karin Muglach, Xudong Sun
Black - vertical magnetic field, Red - horizontal magnetic field,
Blue,
Horizontal
velocities.
Early
HMI Magneticplasma
Field Observations
Preliminary HMI Results
NLFFF Model Result,
2010.04.08
T. Wiegelmann & X. Sun
Disambiguated Vector Field
March 29, 2010
K.D. Leka, G. Barnes, X. Sun
Early HMI Magnetic Field Observations
Disambiguated Bx
Early HMI Magnetic Field Observations
HMI Space Weather and Quick-Look Browsing Products II
– Synoptic Maps
• Synchronic Frame - radial field estimate - 96-minute, reduced resolution
• Evolved Carrington/Synchronic map - 6 hour
– Far side active region map - daily
– Movie of global sun activity - 54-day, updated daily
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Full-disk Velocity – averaged snapshot every 12 minutes
Full-disk Intensity - 12 minute average
Full-disk Line Depth - 12 minute average
Full-disk and ARP Overlays of AIA and HMI Blos - 90-sec update, movie
Alerts & Indices - 12 minute
• Irradiance, mean field, ARP intensity/flare detection
Movies of ARPs in Intensity (updated hourly)
Horizontal Flow from LCT in ARPs (daily)
Coronal Field Models (daily, weekly)
• Global - PFSS, Hybrid - HCCSSS, MHD
• ARPs/Local - PF, NLFFF, MHD
• Field line maps, source surface maps, AIA overlays, MHD quantities
Magnetic field global harmonic coefficients - daily
1 AU Predictions - WSA velocity, polarity, field strength, etc (daily)
Coronal Holes - open foot points (daily)
Polar Field Estimate (monthly)
Note: Not all products are produced by HMI.
Early HMI Magnetic Field Observations
HMI Space Weather and Quick-Look Browsing Products
•
HMI space weather and browse products can be computed in near real time from quick look data.
They may be used for space weather forecasting or real time monitoring and display. They should
not be used for scientific analysis, except perhaps to compare the quality of preliminary and
definitive products.
•
HMI space weather and quick-look products will be coordinated with the Heliophysics Events
Knowledge Base. These data products will complement the AIA Quick Look Browse Products
•
Proposed Space Weather Product LIST – Comments welcome! This list is preliminary and is not a
commitment. Each product must have a prospective user.
•
Full Disk
– Line-of-sight magnetograms (Blos) - 90-sec; 1K*1K resolution
– Vector magnetogram, inverted & disambiguated - 12 hour
– Movie of Blos - 12-day history, frames updated each 90 seconds
•
Active Region Patches (ARPs)
– Identification of active region patches - 12 minute (hourly?)
– Vector magnetic field in major ARPs, disambiguated - 12 minute
– Time series of major ARP indices (since appearance, updated every 12 min
• Location, orientation, separation, total flux, net flux, delta-B,helicity, non-potentiality,
complexity, field gradient, other
– Alerts based on indices
• Increased time resolution during alerts
– Blos at full spatial resolution in ARPs - updated each 90 seconds
Early HMI Magnetic Field Observations
Magnetic Field Modules
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Time Average_IQUV
Stokes Inversion
Field Disambiguation
Bx By Bz Coordinate
Transform
Br Bth Bph Transform
Btot Inc Az Transform
VectorB_Remap/Interpolate
VectorB Spatial Average
VectorB Temporal Average
Carrington Synoptic Chart
Synchronic Map & Frame
Polar Field Extrapolation
PFSS Model & Magnetic
Harmonic Coefficients
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Inferred Horizontal Flows
Non Linear Force Free Field
MHD Model Active Regions
MHD Model Global Corona
Solar Wind Model
Model Heliospheric Conditions
Space Weather Products
HMI_Mean Field
Associated HMI Pipeline Modules
• AR Patch ID & Tracking
• Feature Recognition
• Spatial Averaging
Early HMI Magnetic Field Observations