Solar Physics Common pitfalls

Misconceptions, sign errors, naming traps, and project-specific gotchas.

Modelling mistakes

• Treating field-line plots as proof of correctness. Pretty loops can still violate $\nabla \cdot \mathbf{B}=0$ or force-freeness. See NF2 diagnostics for physical credibility.
• Saying NF2 replaces physics. Better: NF2 is a neural representation/optimiser for a physics-constrained inverse problem.
• Forgetting that the photospheric boundary is not perfectly force-free. See Photosphere versus corona force-free assumption.
• Comparing NF2 only to itself. A potential-field baseline is the first sanity check.

Equation / concept mistakes

• Potential field does not mean weak field; it means current-free: $\nabla \times \mathbf{B}=0$.
• Force-free does not mean no magnetic field. It means $\mathbf{J}\times \mathbf{B}=0$, so current is parallel to field.
• NLFFF allows spatially varying $\alpha$ in $\nabla \times \mathbf{B}=\alpha \mathbf{B}$.
• Solenoidal means no fake magnetic sources/sinks: $\nabla \cdot \mathbf{B}=0$.

Data / coordinate mistakes

• Do not confuse SHARP data product with HARP active-region patch ID. SHARP is the data product; HARP is the patch identifier.
• Do not casually remove the NF2 sign convention $B_y=-B_t$. See NF2 FITS loader component conventions.
• Do not feed field/inclination/azimuth/disambig into a config expecting Br/Bp/Bt. See HMI SHARP field inclination azimuth disambig.

Parent / nearby maps

• Solar Physics index
• Solar Physics Equations and definitions