Magnetar Outbursts From Avalanches of Hall Waves and Crustal Failures

Li, Xinyu; Levin, Y.; Beloborodov, Andrei M.

doi:10.3847/1538-4357/833/2/189

Cited by 77 publications

(80 citation statements)

References 58 publications

(74 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Perhaps 3D simulations announced in Ref. [39] will reveal a closer coincidence with the results of our model.…”

Section: Application For the Description Of Bursts Of Magnetarsmentioning

confidence: 76%

“…For example, the initial magnetic field in the magnetar core necessary to induce a short wavelength Hall wave, which then can trigger TPW, was found in Ref. [39] to have ∼ 10 m length scale, which is only one order of magnitude bigger than Λ max used in Sec. 3 to simulate a giant flare; cf.…”

Section: Application For the Description Of Bursts Of Magnetarsmentioning

confidence: 99%

“…[39], there was a suggestion that magnetar flares can be associated with small scale magnetic fields in the stellar core. For example, the initial magnetic field in the magnetar core necessary to induce a short wavelength Hall wave, which then can trigger TPW, was found in Ref.…”

Section: Application For the Description Of Bursts Of Magnetarsmentioning

confidence: 99%

See 2 more Smart Citations

Magnetic fields in turbulent quark matter and magnetar bursts

Dvornikov

2017

Int. J. Mod. Phys. D

View full text Add to dashboard Cite

We analyze the magnetic field evolution in dense quark matter with unbroken chiral symmetry, which can be found inside quark and hybrid stars. The magnetic field evolves owing to the chiral magnetic effect in the presence of the electroweak interaction between quarks. In our study, we also take into account the magnetohydrodynamic turbulence effects in dense quark matter. We derive the kinetic equations for the spectra of the magnetic helicity density and the magnetic energy density as well as for the chiral imbalances. On the basis of the numerical solution of these equations, we find that turbulence effects are important for the behavior of small scale magnetic fields. It is revealed that, under certain initial conditions, these magnetic fields behave similarly to the electromagnetic flashes of some magnetars. We suggest that fluctuations of magnetic fields, described in frames of our model, which are created in the central regions of a magnetized compact star, can initiate magnetar bursts.

show abstract

“…Perhaps 3D simulations announced in Ref. [39] will reveal a closer coincidence with the results of our model.…”

Section: Application For the Description Of Bursts Of Magnetarsmentioning

confidence: 76%

Section: Application For the Description Of Bursts Of Magnetarsmentioning

confidence: 99%

See 1 more Smart Citation

Magnetic fields in turbulent quark matter and magnetar bursts

Dvornikov

2017

Int. J. Mod. Phys. D

View full text Add to dashboard Cite

show abstract

“…We remark that the timescales here are longer than the instantaneous deposition of thermal energy used in cooling models (Pons & Rea 2012), however, for thin current sheets, the generation of Ohmic heat can be as short as few days and will not have a major impact on the post-burst cooling of the magnetar. Another possibility is that this instability operates in conjunction or trigger other types of instabilities suggested to operate in the outer curst, such as the thermoresistive instability (Price et al 2012) or the thermoplastic instability (Beloborodov & Levin 2014;Li et al 2016), with the major effect of the tearing mode being on the reduction of the timescales and an increase on the energy efficiency.…”

Section: Neutron Star Crust Heating and Outburstsmentioning

confidence: 99%

Resistive tearing instability in electron MHD: application to neutron star crusts

Gourgouliatos¹,

Hollerbach²

2016

Mon. Not. R. Astron. Soc.

View full text Add to dashboard Cite

We study a resistive tearing instability developing in a system evolving through the combined effect of Hall drift in the Electron-MHD limit and Ohmic dissipation. We explore first the exponential growth of the instability in the linear case and we find the fastest growing mode, the corresponding eigenvalues and dispersion relation. The instability growth rate scales as γ ∝ B 2/3 σ −1/3 where B is the magnetic field and σ the electrical conductivity. We confirm the development of the tearing resistive instability in the fully non-linear case, in a plane parallel configuration where the magnetic field polarity reverses, through simulations of systems initiating in Hall equilibrium with some superimposed perturbation. Following a transient phase, during which there is some minor rearrangement of the magnetic field, the perturbation grows exponentially. Once the instability is fully developed the magnetic field forms the characteristic islands and X-type reconnection points, where Ohmic decay is enhanced. We discuss the implications of this instability for the local magnetic field evolution in neutron stars' crusts, proposing that it can contribute to heating near the surface of the star, as suggested by models of magnetar post-burst cooling. In particular, we find that a current sheet a few meters thick, covering as little as 1% of the total surface can provide 10 42 erg in thermal energy within a few days. We briefly discuss applications of this instability in other systems where the Hall effect operates such as protoplanetary discs and space plasmas.

show abstract

“…The crust is treated here as a rigid solid, while in principle it may deform, elastically or plastically and even fail (Beloborodov & Levin 2014;Thompson et al 2017). These effects have been explored in one-dimensional and axially symmetric calculations: the elastic response of the crust is not sufficient to impede Hall evolution (Bransgrove et al 2018), whereas the plastic flows are indeed important close to the surface of the neutron star and lead to Hall avalanches (Li et al 2016). We remark that the result of the above mentioned studies, however, suggest that the dominant driving mechanism of the magnetic field evolution in the bulk of the crust, in the range of strengths explored in this work, remains the Hall drift, and the other effects may be important locally or lead to migration of the magnetic spots toward cooler regions.…”

Section: Discussionmentioning

confidence: 99%

Magnetic Axis Drift and Magnetic Spot Formation in Neutron Stars with Toroidal Fields

Gourgouliatos

Hollerbach

2017

ApJ

View full text Add to dashboard Cite

We explore magnetic field configurations that lead to the formation of magnetic spots on the surface of neutron stars, and to the displacement of the magnetic dipole axis. We find that a toroidally dominated magnetic field is essential for the generation of a single spot with a strong magnetic field. Once a spot forms, it survives for several million years, even after the total magnetic field has decayed significantly. We find that the dipole axis is not stationary with respect to the neutron star's surface and does not in general coincide with the location of the magnetic spot. This is due to non-axisymmetric instabilities of the toroidal field that displace the poloidal dipole axis at rates that may reach 0.4 • per century. A misaligned poloidal dipole axis with the toroidal field leads to more significant displacement of the dipole axis than the fully aligned case. Finally we discuss the evolution of neutron stars with such magnetic fields on the P− Ṗ diagram and the observational implications. We find that neutron stars spend a very short time before they cross the Death-Line of the P − Ṗ diagram, compared to their characteristic ages. Moreover, the maximum intensity of their surface magnetic field is substantially higher than the dipole component of the field. We argue that SGR 0418+5729 could be an example of this type of behaviour, having a weak dipole field, yet hosting a magnetic spot responsible for its magnetar behaviour. The evolution on the pulse profile and braking index of the Crab pulsar, which are attributed to an increase of its obliquity, are compatible with the anticipated drift of the magnetic axis.

show abstract

Magnetar Outbursts From Avalanches of Hall Waves and Crustal Failures

Cited by 77 publications

References 58 publications

Magnetic fields in turbulent quark matter and magnetar bursts

Magnetic fields in turbulent quark matter and magnetar bursts

Resistive tearing instability in electron MHD: application to neutron star crusts

Magnetic Axis Drift and Magnetic Spot Formation in Neutron Stars with Toroidal Fields

Contact Info

Product

Resources

About