Skip to main content Accessibility help
×
Home

The onset of electron-only reconnection

  • Alfred Mallet (a1)

Abstract

Motivated by recent observations of ‘electron-only’ magnetic reconnection, without an ion-scale sheet or ion outflows, in both the Earth’s magnetosheath and in numerical simulations, we study the formation and reconnection of electron-scale current sheets at low plasma $\unicode[STIX]{x1D6FD}$ . We first show that ideal sheets collapse to thicknesses much smaller than the ion scales, by deriving an appropriate analogue of the Chapman–Kendall collapse solution. Second, we show that, in practice, reconnection onset happens in these collapsing sheets once they reach a critical aspect ratio, because the tearing instability then becomes faster than their collapse time scale. We show that this can happen for sheet thicknesses larger than the ion scale or at only a few times the electron scale, depending on plasma parameters and the aspect ratio of the collapsing structure, thereby unifying the usual picture of ion-coupled reconnection and the new regime of electron-only reconnection. We derive relationships between plasma $\unicode[STIX]{x1D6FD}$ , ion-to-electron temperature ratio, the aspect ratio, electron outflow velocity and the final thickness of the sheets, and thus determine under what circumstances electron-scale sheets form and reconnect.

  • View HTML
    • Send article to Kindle

      To send this article to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle.

      Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

      Find out more about the Kindle Personal Document Service.

      The onset of electron-only reconnection
      Available formats
      ×

      Send article to Dropbox

      To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Dropbox.

      The onset of electron-only reconnection
      Available formats
      ×

      Send article to Google Drive

      To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Google Drive.

      The onset of electron-only reconnection
      Available formats
      ×

Copyright

Corresponding author

Email address for correspondence: alfred.mallet@berkeley.edu

References

Hide All
Alexandrova, O. 2008 Solar wind versus magnetosheath turbulence and Alfvén vortices. Nonlin. Proc. Geophys. 15, 95.
Avinash, K., Bulanov, S. V., Esirkepov, T., Kaw, P., Pegoraro, F., Sasorov, P. V. & Sen, A. 1998 Forced magnetic field line reconnection in electron magnetohydrodynamics. Phys. Plasmas 5 (8), 28492860.
Biskamp, D. 2000 Magnetic Reconnection in Plasmas. Cambridge University Press.
Boldyrev, S. 2006 Spectrum of magnetohydrodynamic turbulence. Phys. Rev. Lett. 96, 115002.
Boldyrev, S. & Loureiro, N. F.2019 Role of reconnection in inertial kinetic-Alfvén turbulence. Phys. Rev. Research, doi:10.1103/PhysRevResearch.1.012006.
Bulanov, S. V., Pegoraro, F. & Sakharov, A. S. 1992 Magnetic reconnection in electron magnetohydrodynamics. Phys. Fluids B 4 (8), 24992508.
Califano, F., Cerri, S. S., Faganello, M., Laveder, D. & Kunz, M. W.2018 Electron-only magnetic reconnection in plasma turbulence. arXiv:1810.03957.
Chandran, B. D. G., Schekochihin, A. A. & Mallet, A. 2015 Intermittency and alignment in strong RMHD turbulence. Astrophys. J. 807, 39.
Chapman, S. & Kendall, P. C. 1963 Liquid instability and energy transformation near a magnetic neutral line: a soluble non-linear hydromagnetic problem. Proc. R. Soc. Lond. A 271, 435448.
Chen, C. H. K. & Boldyrev, S. 2017 Nature of kinetic scale turbulence in the Earth’s magnetosheath. Astrophys. J. 842, 122.
Del Sarto, D., Pucci, F., Tenerani, A. & Velli, M. 2016 ‘Ideal’ tearing and the transition to fast reconnection in the weakly collisional MHD and EMHD regimes. J. Geophys. Res. (Space Physics) 121, 18571873.
Fox, N. J., Velli, M. C., Bale, S. D., Decker, R., Driesman, A., Howard, R. A., Kasper, J. C., Kinnison, J., Kusterer, M., Lario, D. et al. 2016 The Solar Probe Plus mission: humanity’s first visit to our star. Space Sci. Rev. 204, 7.
Furth, H. P., Killeen, J. & Rosenbluth, M. N. 1963 Finite-resistivity instabilities of a sheet pinch. Phys. Fluids 6, 459484.
Grošelj, D., Cerri, S. S., Bañón Navarro, A., Willmott, C., Told, D., Loureiro, N. F., Califano, F. & Jenko, F. 2017 Fully kinetic versus reduced-kinetic modeling of collisionless plasma turbulence. Astrophys. J. 847, 28.
Jain, N., von Stechow, A., Muñoz, P. A., Büchner, J., Grulke, O. & Klinger, T. 2017 Electron-magnetohydrodynamic simulations of electron scale current sheet dynamics in the vineta. II guide field reconnection experiment. Phys. Plasmas 24 (9), 092312.
Ji, H., Alt, A., Antiochos, S., Baalrud, S., Bale, S., Bellan, P. M., Begelman, M., Beresnyak, A., Blackman, E. G., Brennan, D. et al. 2019 Major Scientific Challenges and Opportunities in Understanding Magnetic Reconnection and Related Explosive Phenomena throughout the Universe. In Bulletin of the American Astronomical Society, BAAS, vol. 51, p. 5.
Loureiro, N. F., Schekochihin, A. A. & Cowley, S. C. 2007 Instability of current sheets and formation of plasmoid chains. Phys. Plasmas 14 (10), 100703.
Mallet, A. & Schekochihin, A. A. 2017 A statistical model of three-dimensional anisotropy and intermittency in strong alfvénic turbulence. Mon. Not. R. Astron. Soc. 466, 3918.
Mallet, A., Schekochihin, A. A. & Chandran, B. D. G. 2017 Disruption of Alfvénic turbulence by magnetic reconnection in a collisionless plasma. J. Plasma Phys. 83 (6), 905830609.
Mandt, M. E., Denton, R. E. & Drake, J. F. 1994 Transition to whistler mediated magnetic reconnection. Geophys. Res. Lett. 21, 7376.
Numata, R. & Loureiro, N. F. 2015 Ion and electron heating during magnetic reconnection in weakly collisional plasmas. J. Plasma Phys. 81, 305810201.
Parker, E. N. 1957 Sweet’s mechanism for merging magnetic fields in conducting fluids. J. Geophys. Res. 62, 509520.
Phan, T. D., Eastwood, J. P., Shay, M. A., Drake, J. F., Sonnerup, BU. Ö., Fujimoto, M., Cassak, P. A., Øieroset, M., Burch, J. L., Torbert, R. B. et al. 2018 Electron magnetic reconnection without ion coupling in earths turbulent magnetosheath. Nature 557 (7704), 202.
Pucci, F. & Velli, M. 2014 Reconnection of quasi-singular current sheets: the ‘ideal’ tearing mode. Astrophys. J. Lett. 780, L19.
Rogers, B. N., Denton, R. E., Drake, J. F. & Shay, M. A. 2001 Role of dispersive waves in collisionless magnetic reconnection. Phys. Rev. Lett. 87, 195004.
Schekochihin, A. A., Cowley, S. C., Dorland, W., Hammett, G. W., Howes, G. G., Quataert, E. & Tatsuno, T. 2009 Astrophysical gyrokinetics: kinetic and fluid turbulent cascades in magnetized weakly collisional plasmas. Astrophys. J. Supp. 182, 310.
Sharma Pyakurel, P., Shay, M. A., Phan, T. D., Matthaeus, W. H., Drake, J. F., TenBarge, J. M., Haggerty, C. C., Klein, K., Cassak, P. A., Parashar, T. N. et al. 2019 Transition from ion-coupled to electron-only reconnection: basic physics and implications for plasma turbulence. Phys. Plasmas, doi:10.1063/1.5090403.
Stawarz, J. E., Eastwood, J. P., Phan, T. D., Gingell, I. L., Shay, M. A., Burch, J. L., Ergun, R. E., Giles, B. L., Gershman, D. J., Le Contel, O. et al. 2019 Properties of the turbulence associated with electron-only magnetic reconnection in Earth’s magnetosheath. Astrophys. J. Lett. 877, L37.
Strauss, H. R. 1976 Nonlinear, three-dimensional magnetohydrodynamics of noncircular tokamaks. Phys. Fluids 19, 134.
Sundkvist, D. & Bale, S. D. 2008 Characteristic parameters of drift vortices coupled to Alfvén waves in an inhomogeneous space plasma. Phys. Rev. Lett. 101, 065001.
Sweet, P. A. 1958 The neutral point theory of solar flares. In Electromagnetic Phenomena in Cosmical Physics (ed. Lehnert, B.), IAU Symposium, vol. 6, p. 123. CUP.
Syrovatskii, S. I. 1981 Pinch sheets and reconnection in astrophysics. Annu. Rev. Astron. Astrophys. 19 (1), 163227.
Tenerani, A., Velli, M., Pucci, F., Landi, S. & Rappazzo, A. F. 2016 Ideally unstable current sheets and the triggering of fast magnetic reconnection. J. Plasma Phys. 82 (5), 535820501.
Uzdensky, D. A. & Loureiro, N. F. 2016 Magnetic reconnection onset via disruption of a forming current sheet by the tearing instability. Phys. Rev. Lett. 116 (10), 105003.
Wesson, J. A. 1990 Sawtooth reconnection. Nucl. Fusion 30 (12), 2545.
White, R. L., Hazeltine, R. D. & Loureiro, N. F. 2018 Symmetries of a reduced fluid-gyrokinetic system. J. Plasma Phys. 84 (2), 905840204.
Yamada, M., Kulsrud, R. & Ji, H. 2010 Magnetic reconnection. Rev. Mod. Phys. 82, 603664.
Zocco, A. & Schekochihin, A. A. 2011 Reduced fluid-kinetic equations for low-frequency dynamics, magnetic reconnection, and electron heating in low-beta plasmas. Phys. Plasmas 18, 102309.
Zweibel, E. G. & Yamada, M. 2009 Magnetic reconnection in astrophysical and laboratory plasmas. ARA&A 47, 291332.
MathJax
MathJax is a JavaScript display engine for mathematics. For more information see http://www.mathjax.org.

Keywords

The onset of electron-only reconnection

  • Alfred Mallet (a1)

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed.