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From proto-neutron star dynamo to low-field magnetars

T0 review · 4 major / 5 minor · reviewed 2026-08-10 · deepseek-v4-flash

Pith's one-line read Low-field magnetars can form through a Tayler–Spruit dynamo, not by aging from classical magnetar fields, according to the first dynamo-seeded magneto-thermal simulations.

desk verdict First dynamo-to-crust evolution study; the weak dipole and polar cracking are genuine outputs, but the result hinges on an unmotivated core-field expulsion. read the letter →

arxiv 2501.04768 v1 pith:FORPLMT4 submitted 2025-01-08 astro-ph.HE

classification astro-ph.HE
keywords neutronstarsmagnetarslow-fieldTayler-Spruitdynamoproto-neutronstarmagneto-thermalevolutioncrustalmagneticfieldX-raybursts
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

This paper argues that low-field magnetars—neutron stars whose dipolar fields are 10–100 times weaker than the classical magnetar threshold yet that still emit X-ray bursts—are formed through a Tayler–Spruit dynamo in the proto-neutron star, rather than being aged classical magnetars. The argument is built by coupling two simulations: a magnetohydrodynamic dynamo calculation that produces a crust-confined magnetic field, and a one-million-year magneto-thermal evolution of that field inside the neutron-star crust. The resulting surface field has a weak dipole (rising to about $1.5\times10^{12}$ G) and strong small-scale components about 100 times larger, matching the two defining observations of low-field magnetars. The same configuration develops crustal stresses above the yielding threshold near the magnetic poles, providing an energy reservoir consistent with observed bursts. A reader should care because this connects an observable population of 5 of the 30 known magnetars to a specific dynamo mechanism and suggests two distinct formation channels.

What carries the argument

The central mechanism is the Tayler–Spruit dynamo—a magnetohydrodynamic process in which differential rotation in a stably stratified proto-neutron star sustains a magnetic field through instability—and the load-bearing object is the specific field configuration it produces. That configuration, extracted from the top 10% of the dynamo volume and assumed to be confined to the crust, is predominantly toroidal and localised near the polar regions. The argument then runs on the magneto-thermal evolution of this seed: a coupled magnetic-induction and thermal-diffusion calculation over 1 Myr, a von Mises criterion for crustal yielding, and a fallback-disk torque model for spin-down. Because the seed already contains strong small-scale and weak large-scale components, the evolution preserves that hierarchy, which is what ultimately yields weak dipoles, strong local fields, polar crust failures, and 8–11 s spin periods.

What would settle it

Run the magneto-thermal evolution from the full dynamo-generated field without the crust-confined truncation; if the surface dipolar field at ages between 0.1 and 1 Myr exceeds roughly $10^{13}$ G, the mechanism cannot account for the observed low-field magnetars. A complementary observational check would be to measure the dipole field of a young low-field magnetar candidate at an age below 200 kyr and see whether it lies near the simulated value of about $10^{12}$ G rather than at the classical magnetar scale.

Watch

Extended reading notes

Core claim

The central claim is that the properties of low-field magnetars can be reproduced, for the first time, by starting magneto-thermal evolution from a magnetic field produced by a direct numerical simulation of the Tayler–Spruit dynamo, rather than from idealized configurations. In the simulation, the dynamo field inside the proto-neutron star is predominantly toroidal and reaches up to $3\times10^{15}$ G, but after the assumed expulsion of the core field only the outer crust retains a weak, complex field. Over one million years the dipole grows by only a factor of about three, reaching $1.5\times10^{12}$ G, while small-scale fields of order $10^{14}$ G persist at the footpoints of elongated magnetic arches. Crustal yielding occurs near the poles, and magnetospheric currents at the strongest footpoints produce small hot spots whose synthetic lightcurves reach pulsed fractions of up to 93%, consistent with observations. Fallback-disk propeller torques then spin the neutron star down to periods of 8–11 s around 170 kyr, with period derivatives that cover the range measured for low-field magnetars.

Load-bearing premise

The match rests on the assumption that the $3\times10^{15}$ G field generated deep inside the proto-neutron star is expelled, leaving only a crust-confined configuration whose weak outer field determines the dipole; if that deep field stays connected to the surface, the predicted dipole would overshoot the observed values.

Editorial extensions

If this is right

  • Low-field magnetars would not be old classical magnetars: they are born with weak dipoles and strong crust-confined fields through a distinct dynamo channel.
  • The surface dipole of a neutron star formed this way stays below about $2\times10^{12}$ G for at least 1 Myr, so evolutionary scenarios that require a decaying $10^{14}$ G dipole are unnecessary.
  • Crust failures and bursts from this configuration occur near the magnetic poles, in contrast to the equatorial failures found with dipolar initial conditions; burst energy release is bounded by roughly $2\times10^{39}$ erg.
  • Spin-down to the observed 8–11 s periods requires a fallback disk operating in the propeller phase; inferred dipoles from $P$ and $\dot{P}$ then overestimate the true surface field by about a factor of 40.
  • If the fallback disk depletes, the same formation path ends at periods of about 75 s, linking low-field magnetars to the recently discovered long-period radio pulsars.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • A control simulation that keeps the full dynamo field without the expelling truncation would show how much of the result depends on the crust-confined assumption; if that run produces a strong surface dipole, the low-field channel fails for fields that are not expelled.
  • Seeding the same magneto-thermal evolution with fields from other dynamo mechanisms (convective or magnetorotational-instability dynamos) would predict different burst latitudes and dipole growth, giving observers a way to identify which dynamo operated in a given neutron star.
  • The propeller spin-down model implies that the true surface dipoles of some low-field magnetars are much smaller than values inferred from $P$ and $\dot{P}$; a population study that accounts for the fallback disk should find objects whose apparent dipoles cluster near the $10^{13}$ G boundary while their true dipoles are near $10^{12}$ G.
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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

4 major / 5 minor

Summary. This paper presents the first magneto-thermal evolution simulations of a neutron-star crust initialized with a magnetic field from a direct numerical simulation of the Tayler–Spruit dynamo in a proto-neutron star. The authors extract the outer 10% of the dynamo field as a crust-confined initial condition, evolve it for 1 Myr with the PARODY code, and show that the resulting field has a weak dipolar component (~1e12 G), strong small-scale fields, localized hot spots, and crustal failure regions near the poles. They further show that fallback-disk propeller spin-down can produce the 8–11 s periods of low-field magnetars. They argue this supports a distinct formation channel for low-field magnetars compared with classical magnetars.

Significance. If the results hold, this is a significant step: it is the first attempt to connect a specific dynamo mechanism (Tayler–Spruit) to the observed phenomenology of low-field magnetars using direct numerical simulations of the initial field, rather than idealized configurations. The paper explicitly identifies several falsifiable predictions, such as the predominance of small-scale fields, polar crust-failure locations, and a moderate dipole growth over 1 Myr. The manuscript is generally well written, and the numerical setup for the crust evolution is detailed and internally consistent. The principal weakness is that the central link between the dynamo simulation and the crust-confined initial condition rests on an unmodeled assumption (core-field expulsion), and the analysis uses a single dynamo realization without sensitivity tests.

major comments (4)
  1. [Main text, §2 and Methods §2–3] The assumption that the core magnetic field is expelled, leaving only the top 10% of the dynamo field, is load-bearing for all subsequent results. The dynamo simulation produces fields up to 3e15 G in the deep core, and the extraction procedure discards the inner 90% of the volume. The paper does not model the expulsion mechanism, nor does it justify why the field near the outer boundary should be representative of the post-expulsion crustal field. If flux is conserved during expulsion, the deep-core flux compressed into the thin crust would produce significantly stronger crustal fields than the extracted top-10% field. If the core field is not expelled, the external poloidal field would likely be orders of magnitude stronger than the observed low-field values. The predicted weak dipole, strong small-scale fields, and crust-failure locations all depend directly on this assumed configuration. The authors should either provide a physical model for the expulsion or perform a sensitivity study varying the extraction depth and including a residual core poloidal field, to demonstrate that the conclusions are not artifacts of this choice.
  2. [Main text, 'Evolution of neutron star magnetic field' and Methods §1] Only one dynamo realization is used as the initial condition, at a single set of dynamo parameters (Omega_o = 4 Omega_i = 628 rad/s). No error bars, no ensemble runs, and no exploration of the dependence on the dynamo snapshot or parameters are provided. The claim that the simulation 'naturally explains' the properties of low-field magnetars requires demonstrating that these properties are generic to the Tayler–Spruit dynamo branch rather than a coincidence of this particular field configuration. At a minimum, the authors should analyze multiple dynamo snapshots or multiple runs with varied parameters (e.g., rotation rate, Rayleigh number) and show that the qualitative outcome—weak dipole, small-scale dominance, polar crust failure—is robust.
  3. [Main text, 'Surface temperatures and hot spots' and Methods §5] The hot spot threshold |Br| > 7e13 G is introduced without a first-principles derivation; it is a free parameter chosen to reproduce observed pulsed fractions and hot-spot sizes (up to 10 spots, pulsed fraction up to 92%, radius ~0.9 km). The statement that the model 'naturally explains' these features is therefore weakened by this tuning. The authors should quantify the sensitivity of the predicted pulsed fractions and spot properties to this threshold, and state whether any physically plausible threshold within the model's range yields the observed diversity of low-field magnetars.
  4. [Methods §7 and Figure 5] The spin-down calculation uses a constant dipolar field BNS as a free parameter (fiducially 1e12 G) rather than the time-dependent dipole field from the magneto-thermal simulation. The simulation shows that the surface dipole grows by a factor of ~3 during the first Myr, which could affect the propeller torque and the inferred P–Pdot evolution. The authors should test whether using the simulated time-dependent dipole modifies the conclusion that periods of 8–11 s are reached at ~170 kyr, and discuss the resulting uncertainty in the apparent dipole inferred from P and Pdot.
minor comments (5)
  1. [Methods §3, Eq. (24)] Equation (24) contains a typo: the polynomial is written as a0 + a1 r + a2 r^2 + a3 r^2 + a4 r^4 / r, but the matching linear system in Eq. (26) uses a3 r^3; the middle term should be a3 r^3.
  2. [Table 1] The column headers in Table 1 (χ, i, ∆Φ, C-stat) are not defined in the caption; please define the obliquity, inclination, phase offset, and fit statistic explicitly.
  3. [Main text, 'Surface temperatures and hot spots'] The sentence 'These variations could cause up to 20 % pulsed fraction but would stay undetectable because of the low bulk X-ray luminosity...' is confusing: if the emission is undetectable, the pulsed fraction is irrelevant. Clarify that the thermal variations alone produce a pulsed fraction too small and a luminosity too low to match observations, motivating the magnetospheric heating scenario.
  4. [Reference [4]] Reference [4] is formatted awkwardly, with the editors named in the middle of the citation; this appears to be an incomplete or corrupted entry and should be corrected.
  5. [Methods §4, Eq. (29)] The Biermann battery term is included in the induction equation but is not discussed in the text; a brief justification of its expected magnitude and effect on the results would be helpful.

Circularity Check

1 steps flagged · score 2.0 of 10

Mild circularity in the hot-spot model; core dynamo-origin claim rests on separate, non-fitted inputs.

  1. fitted input called prediction [Main text, 'Surface temperatures and hot spots' section]
    "Here we assume that only footpoints with radial magnetic field |Br| > 7 × 10^13 G are heated. Under this assumption, it is possible to form up to 10 independent hot spots (see Figure 3) which, if heated to 3 × 10^6 K, produce luminosity 2 × 10^32 erg/s and emission area with radius ≈ 0.9 km. The lightcurve is sine-like with a pulsed fraction reaching 92% for a favourable orientation even without beaming, in agreement with X-ray observations of low-field magnetars."

    The threshold |Br|>7×10^13 G, the spot temperature 3×10^6 K, and the 'favourable orientation' are free inputs; the orientation angles are explicitly fitted to the observed lightcurves in Methods Table 1. The predicted hot-spot radius (~0.9 km), luminosity, and pulsed fraction (up to 92%) are direct outputs of these parameter choices, while the observed hot-spot sizes (≤1 km) and pulsed fractions (38–80%) are the quantities from which these inputs are effectively selected. Therefore the claimed agreement is partly by construction rather than a parameter-free prediction. This does not affect the core dynamo-origin claim, but it overstates the support drawn from the hot-spot model.

full rationale

The central chain — Tayler-Spruit dynamo simulation, extraction of the outer 10%, magneto-thermal evolution with PARODY, and comparison of dipole strength, small-scale fields, crustal failure sites, and spin periods — is largely self-contained. The dynamo initial condition is taken from the authors' own prior MHD simulation, but that simulation was not tuned to match low-field magnetars, and the crust evolution is an independent calculation with no fitting to the target observables. The weak surface dipole follows from the explicit assumption that the core field is expelled, which is an unmodeled scenario rather than a circular derivation. The only notable circularity is in the hot-spot section, where the radial-field threshold and spot temperature are free parameters and the orientation is fitted per object; the resulting hot-spot sizes and pulsed fractions are therefore not independent predictions, though they do demonstrate consistency. No self-citation is load-bearing in a way that forces the conclusion; the dynamo simulations are code-based and reproducible. Overall score 2.

Assumptions & free parameters 6 free parameters · 5 assumptions · 0 invented entities

The central simulation rests on the dynamo simulation, the crust-confined extraction, and published crust and disk models. The main free choices are the extraction depth, the hot spot threshold, and the fallback disk parameters. No new particles, forces, or conserved quantities are introduced.

free parameters (6)
  • Hot spot threshold |Br| = 7e13 G
    Chosen to produce the observed number and size of hot spots; varying it changes spot count and area.
  • Hot spot temperature = 3e6 K
    Assumed temperature of heated footpoints to match observed blackbody temperatures in lightcurve fits.
  • Fallback disk mass Md,0 = 0.01 M_sun
    Initial disk mass in the spin-down model; variations are shown in Figure 5, but the value is not tightly constrained.
  • Initial spin period = 10 ms
    Assumed initial rotation consistent with the slow-rotation, fallback-driven Tayler-Spruit scenario.
  • Dipole field for spin-down BNS = 1e12 G
    Approximately the simulated surface dipole strength; the resulting period evolution is sensitive to this value.
  • Crust-confined extraction depth = top 10% of dynamo volume
    Ad hoc choice to construct the crust-confined initial condition; it directly determines the strength of the external field.
assumptions (5)
  • domain assumption The MagIC proto-NS simulation faithfully represents the Tayler-Spruit dynamo in a proto-neutron star spun up by fallback.
    The initial magnetic field is taken from this simulation (Section 1, ref [27]), and its realism is not re-derived here.
  • ad hoc to paper The core magnetic field is expelled, leaving a crust-confined configuration.
    Main text: 'Assuming a scenario in which the core magnetic field is expelled to a crust-confined configuration'; this is load-bearing for the weak surface dipole result.
  • domain assumption The crust can be modeled with the given electron-MHD equations and boundary conditions.
    Equations 29-30 are taken from ref [54] and are assumed to capture Hall evolution, Ohmic decay, and thermal transport in the crust.
  • domain assumption The von Mises criterion with the given yield stress is the correct crust failure condition.
    Section 6 is based on ref [45], but the critical strain correction in Eq. 43 comes from a private communication by Sam Lander.
  • domain assumption The fallback disk torque model of Ronchi et al. applies to magnetar spin-down.
    Section 7 uses Eqs. 45-51 from ref [48] to model the propeller phase and obtain periods of 8-11 s.

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Cite this review

Pith. "Pith review of From proto-neutron star dynamo to low-field magnetars." pith.science (2026). https://pith.science/paper/FORPLMT4

@misc{pith2026250104768,
  author       = {Pith},
  title        = {Pith review of: From proto-neutron star dynamo to low-field magnetars},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/FORPLMT4}},
  note         = {Machine review of arXiv:2501.04768}
}
abstract

Low-field magnetars have dipolar magnetic fields that are 10-100 times weaker than the threshold, $B \gtrsim 10^{14}$ G, used to define classical magnetars, yet they produce similar X-ray bursts and outbursts. Using the first direct numerical simulations of magneto-thermal evolution starting from a dynamo-generated magnetic field, we show that the low-field magnetars can be produced as a result of a Tayler--Spruit dynamo inside the proto-neutron star. We find that these simulations naturally explain key characteristics of low-field magnetars: (1) weak ($\lesssim 10^{13}$ G) dipolar magnetic fields, (2) strong small-scale fields, and (3) magnetically induced crustal failures producing X-ray bursts. These findings suggest two distinct formation channels for classical and low-field magnetars, potentially linked to different dynamo mechanisms.

Discussion (0). Continue with ORCID to comment.

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Reference graph

Works this paper leans on

57 extracted references · 56 canonical work pages · cited by 2 Pith papers

  1. [1]

    C., Yi, I., H¨ oflich, P

    Wheeler, J. C., Yi, I., H¨ oflich, P. & Wang, L. Asymmetric Supernovae, Pulsars, Magnetars, and Gamma-Ray Bursts. ApJ 537, 810–823 (2000)

  2. [2]

    J., Waldman, R., Livne, E

    Dessart, L., Hillier, D. J., Waldman, R., Livne, E. & Blondin, S. Superluminous supernovae: 56Ni power versus magnetar radiation. MNRAS426, L76–L80 (2012)

  3. [3]

    Greiner, J. et al. A very luminous magnetar-powered supernova associated with an ultra-long γ-ray burst. Nature 523, 189–192 (2015)

  4. [4]

    Popov, S. B. & Postnov, K. A. Harutyunian, H. A., Mickaelian, A. M. & Terzian, Y. (eds) Hyperflares of SGRs as an engine for millisecond extragalactic radio bursts. (eds Harutyunian, H. A., Mickaelian, A. M. & Terzian, Y.) Evolution of Cosmic Objects through their Physical Activity , 129–132 (2010). 0710.2006

  5. [5]

    Bochenek, C. D. et al. A fast radio burst associated with a Galactic magnetar. Nature 587, 59–62 (2020). 9

  6. [6]

    N., Hobbs, G

    Manchester, R. N., Hobbs, G. B., Teoh, A. & Hobbs, M. The Australia Telescope National Facility Pulsar Catalogue. AJ 129, 1993–2006 (2005)

  7. [7]

    Keane, E. F. & Kramer, M. On the birthrates of Galactic neutron stars. MNRAS 391, 2009–2016 (2008)

  8. [8]

    & Duncan, R

    Thompson, C. & Duncan, R. C. Neutron Star Dynamos and the Origins of Pulsar Magnetism. ApJ 408, 194 (1993)

Show all 57 references
  1. [9]

    & Duncan, R

    Thompson, C. & Duncan, R. C. The soft gamma repeaters as very strongly magnetized neutron stars - I. Radiative mechanism for outbursts. MNRAS 275, 255–300 (1995)

  2. [10]

    van der Horst, A. J. et al. Discovery of a New Soft Gamma Repeater: SGR J0418 + 5729. ApJ 711, L1–L6 (2010)

  3. [11]

    Rea, N. et al. A Low-Magnetic-Field Soft Gamma Repeater. Science 330, 944 (2010)

  4. [12]

    Rea, N. et al. A New Low Magnetic Field Magnetar: The 2011 Outburst of Swift J1822.3-1606. ApJ 754, 27 (2012)

  5. [13]

    Scholz, P. et al. Post-outburst X-Ray Flux and Timing Evolution of Swift J1822.3-

  6. [14]

    L., Pons, J

    Rea, N., Vigan` o, D., Israel, G. L., Pons, J. A. & Torres, D. F. 3XMM J185246.6+003317: Another Low Magnetic Field Magnetar. ApJ781, L17 (2014)

  7. [15]

    P., Hollerbach, R., Wood, T

    Igoshev, A. P., Hollerbach, R., Wood, T. & Gourgouliatos, K. N. Strong toroidal magnetic fields required by quiescent X-ray emission of magnetars. Nature Astronomy 5, 145–149 (2021)

  8. [16]

    Tiengo, A. et al. A variable absorption feature in the X-ray spectrum of a magnetar. Nature 500, 312–314 (2013)

  9. [17]

    Rodr ´ ıguez Castillo, G. A.et al. The outburst decay of the low magnetic field mag- netar SWIFT J1822.3-1606: phase-resolved analysis and evidence for a variable cyclotron feature. MNRAS 456, 4145–4155 (2016)

  10. [18]

    & Haskell, B

    Sarin, N., Brandenburg, A. & Haskell, B. Confronting the Neutron Star Population with Inverse Cascades. ApJ 952, L21 (2023)

  11. [19]

    & Gastine, T

    Raynaud, R., Guilet, J., Janka, H.-T. & Gastine, T. Magnetar formation through a convective dynamo in protoneutron stars. Science Advances 6, eaay2732 (2020)

  12. [20]

    & Guilet, J

    Raynaud, R., Cerd´ a-Dur´ an, P. & Guilet, J. Gravitational wave signature of proto- neutron star convection: I. MHD numerical simulations. MNRAS 509, 3410–3426 (2022). 10

  13. [21]

    & Kotake, K

    Masada, Y., Takiwaki, T. & Kotake, K. Convection and Dynamo in Newly Born Neutron Stars. ApJ 924, 75 (2022)

  14. [22]

    J., Burrows, A., Coleman, M

    White, C. J., Burrows, A., Coleman, M. S. B. & Vartanyan, D. On the Origin of Pulsar and Magnetar Magnetic Fields. ApJ 926, 111 (2022)

  15. [23]

    & Bugli, M

    Reboul-Salze, A., Guilet, J., Raynaud, R. & Bugli, M. A global model of the magnetorotational instability in protoneutron stars. A&A 645, A109 (2021)

  16. [24]

    & Bugli, M

    Reboul-Salze, A., Guilet, J., Raynaud, R. & Bugli, M. MRI-driven αΩ dynamos in protoneutron stars. A&A 667, A94 (2022)

  17. [25]

    Spruit, H. C. Dynamo action by differential rotation in a stably stratified stellar interior. A&A 381, 923–932 (2002)

  18. [26]

    & Janka, H

    Barr` ere, P., Guilet, J., Reboul-Salze, A., Raynaud, R. & Janka, H. T. A new scenario for magnetar formation: Tayler-Spruit dynamo in a proto-neutron star spun up by fallback. A&A 668, A79 (2022)

  19. [27]

    & Reboul-Salze, A

    Barr` ere, P., Guilet, J., Raynaud, R. & Reboul-Salze, A. Numerical simulations of the Tayler-Spruit dynamo in proto-magnetars. MNRAS 526, L88–L93 (2023)

  20. [28]

    & Kuiper, L

    Vink, J. & Kuiper, L. Supernova remnant energetics and magnetars: no evidence in favour of millisecond proto-neutron stars. MNRAS 370, L14–L18 (2006)

  21. [29]

    Martin, J., Rea, N., Torres, D. F. & Papitto, A. Comparing supernova remnants around strongly magnetized and canonical pulsars. MNRAS 444, 2910–2924 (2014)

  22. [30]

    & Reisenegger, A

    Goldreich, P. & Reisenegger, A. Magnetic Field Decay in Isolated Neutron Stars. ApJ 395, 250 (1992)

  23. [31]

    P., Popov, S

    Igoshev, A. P., Popov, S. B. & Hollerbach, R. Evolution of Neutron Star Magnetic Fields. Universe 7, 351 (2021)

  24. [32]

    & R¨ udiger, G

    Hollerbach, R. & R¨ udiger, G. Hall drift in the stratified crusts of neutron stars. MNRAS 347, 1273–1278 (2004)

  25. [33]

    Wareing, C. J. & Hollerbach, R. Cascades in decaying three-dimensional elec- tron magnetohydrodynamic turbulence. Journal of Plasma Physics 76, 117–128 (2010)

  26. [34]

    Inner-core conductivity in numerical dynamo simulations

    Wicht, J. Inner-core conductivity in numerical dynamo simulations. Physics of the Earth and Planetary Interiors 132, 281–302 (2002)

  27. [35]

    & Wicht, J

    Gastine, T. & Wicht, J. Effects of compressibility on driving zonal flow in gas giants. Icarus 219, 428–442 (2012). 11

  28. [36]

    Efficient spherical harmonic transforms aimed at pseudospec- tral numerical simulations

    Schaeffer, N. Efficient spherical harmonic transforms aimed at pseudospec- tral numerical simulations. Geochemistry, Geophysics, Geosystems 14, 751–758 (2013)

  29. [37]

    Mod´ elisation Num´ erique de la Dynamo Terrestre

    Dormy, E. Mod´ elisation Num´ erique de la Dynamo Terrestre. Ph.D. thesis, Institut de Physique du Globe de Paris (1997)

  30. [38]

    & Jault, D

    Dormy, E., Cardin, P. & Jault, D. MHD flow in a slightly differentially rotating spherical shell, with conducting inner core, in a dipolar magnetic field. Earth and Planetary Science Letters 160, 15–30 (1998)

  31. [39]

    & Wicht, J

    Aubert, J., Aurnou, J. & Wicht, J. The magnetic structure of convection-driven numerical dynamos. Geophysical Journal International 172, 945–956 (2008)

  32. [40]

    & Pons, J

    Guillot, S., Perna, R., Rea, N., Vigan` o, D. & Pons, J. A. Modelling of the surface emission of the low magnetic field magnetar SGR 0418+5729. MNRAS 452, 3357–3368 (2015)

  33. [41]

    Seo, J., Lee, J. & An, H. Correlation Study of Temporal and Emission Proper- ties of Quiescent Magnetars. Journal of Korean Astronomical Society 56, 41–57 (2023)

  34. [42]

    Potekhin, A. Y. & Chabrier, G. Magnetic neutron star cooling and microphysics. A&A 609, A74 (2018)

  35. [43]

    & Kulkarni, S

    Thompson, C., Lyutikov, M. & Kulkarni, S. R. Electrodynamics of Magnetars: Implications for the Persistent X-Ray Emission and Spin-down of the Soft Gamma Repeaters and Anomalous X-Ray Pulsars. ApJ 574, 332–355 (2002)

  36. [44]

    K., Andersson, N., Antonopoulou, D

    Lander, S. K., Andersson, N., Antonopoulou, D. & Watts, A. L. Magnetically driven crustquakes in neutron stars. MNRAS 449, 2047–2058 (2015)

  37. [45]

    Lander, S. K. & Gourgouliatos, K. N. Magnetic-field evolution in a plastically failing neutron-star crust. MNRAS 486, 4130–4143 (2019)

  38. [46]

    Wood, T. S. & Hollerbach, R. Three Dimensional Simulation of the Magnetic Stress in a Neutron Star Crust. Phys. Rev. Lett. 114, 191101 (2015)

  39. [47]

    Muno, M. P. et al. Exciting the magnetosphere of the magnetar CXOU J164710.2- 455216 in Westerlund 1. MNRAS 378, L44–L48 (2007)

  40. [48]

    & Hurley-Walker, N

    Ronchi, M., Rea, N., Graber, V. & Hurley-Walker, N. Long-period Pulsars as Possible Outcomes of Supernova Fallback Accretion. ApJ 934, 184 (2022)

  41. [49]

    P., Hollerbach, R

    Igoshev, A. P., Hollerbach, R. & Wood, T. Three-dimensional magnetother- mal evolution of off-centred dipole magnetic field configurations in neutron stars. MNRAS 525, 3354–3375 (2023). 12

  42. [50]

    De Grandis, D. et al. Three-dimensional Magnetothermal Simulations of Magnetar Outbursts. ApJ 936, 99 (2022)

  43. [51]

    Dehman, C., Vigan` o, D., Ascenzi, S., Pons, J. A. & Rea, N. 3D evolution of neutron star magnetic fields from a realistic core-collapse turbulent topology. MNRAS 523, 5198–5206 (2023)

  44. [52]

    Caleb, M. et al. Discovery of a radio-emitting neutron star with an ultra-long spin period of 76 s. Nature Astronomy 6, 828–836 (2022)

  45. [53]

    Mahlmann, J. F. et al. Three-dimensional Dynamics of Strongly Twisted Mag- netar Magnetospheres: Kinking Flux Tubes and Global Eruptions. ApJ 947, L34 (2023)

  46. [54]

    De Grandis, D. et al. Three-dimensional Modeling of the Magnetothermal Evolution of Neutron Stars: Method and Test Cases. ApJ 903, 40 (2020)

  47. [55]

    Urpin, V. A. & Yakovlev, D. G. Thermogalvanomagnetic Effects in White Dwarfs and Neutron Stars. Soviet Ast. 24, 425 (1980)

  48. [56]

    H., Pethick, C

    Gudmundsson, E. H., Pethick, C. J. & Epstein, R. I. Structure of neutron star envelopes. ApJ 272, 286–300 (1983)

  49. [57]

    Programme National de Physique Stellaire

    Gompertz, B. P., O’Brien, P. T. & Wynn, G. A. Magnetar powered GRBs: explaining the extended emission and X-ray plateau of short GRB light curves. MNRAS 438, 240–250 (2014). Acknowledgements API and RH are supported by STFC grant no. ST/W000873/1, and TSW is supported by STFC ...

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Reviewed August 10, 2026 · model on record in the stance chip above.