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HMI SHARP CEA vector components

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HMI SHARP CEA vector components

The main CEA vector magnetic-field segments are:

Br
Bp
Bt
Br_err
Bp_err
Bt_err

Use these for normal HMI SHARP CEA NF2 training, time-series runs, and boundary-quality checks.

The three field components

  • Br is the radial component, close to “up” out of the local solar surface.
  • Bp is the heliographic phi component.
  • Bt is the heliographic theta component.

These are already remapped vector components in the CEA patch. They are not the same as field, inclination, and azimuth, which are a polar/inversion-style description.

NF2 convention

The NF2 FITS loader converts the CEA components into its local boundary axes as:

Bx = Bp
By = -Bt
Bz = Br

Equivalently,

The sign flip on Bt is important. Removing it changes the handedness of the field and can corrupt currents, twist, and topology.

Error maps

The matching uncertainty segments are:

Br_err
Bp_err
Bt_err

NF2 stacks them as:

Bx_err = Bp_err
By_err = Bt_err
Bz_err = Br_err

There is no minus sign on Bt_err because an uncertainty is a magnitude. Its sign has no physical meaning.

The transverse components are usually noisier than the normal component, so the error maps are useful for boundary weighting and for judging whether a mismatch is significant.

Graph View

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