London screening and Meissner response
Research context
postgraduate concept · conditional · As of 2026-10-10
In the local London model, ∇×j_s=−n_s q_s²B/m_s.
Key knowledge
In the local London model, ∇×j_s=−n_s q_s²B/m_s. Combined with quasistatic Maxwell equations this gives ∇²B=B/λ_L², where λ_L²=m_s/(μ₀n_s q_s²). A flat half-space screens weak fields exponentially. Persistent conductivity alone does not establish equilibrium flux expulsion.
Values and equations
λ_L²=m_s/(μ₀n_s q_s²); B(x)=B(0)e^(−x/λ_L)
- λ_L,x
- Penetration length and depth m
- m_s
- Effective carrier mass kg
- n_s
- Carrier number density m⁻³
- q_s
- Carrier charge C
- μ₀
- Vacuum permeability H m⁻¹
- B
- Magnetic flux density T
Conditions and scope
- Uniform carrier density, positive effective mass, local response, no vortices and applied field below the relevant breakdown/entry threshold.
- n_s counts the carriers associated with q_s,m_s consistently; pair versus electron conventions must not be mixed. Geometry and nonlocal response modify the solution.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Inspected London equations, quasistatic Maxwell combination and magnetic penetration slides; source check dated 2026-10-10. Scope is limited to the cited statements, equations and assumptions, not the whole publication.
2026-10-10 · Author source inspection of the displayed claim, model assumptions and equations; independent exact-content and branch-inventory review is a separate gate. Contemporary status is a dated snapshot, not a promise of ongoing monitoring.
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