Generation of laboratory nanoflares from multiple braided plasma loops
Solar flares are intense bursts of electromagnetic radiation accompanied by energetic particles and hard X-rays. They occur when magnetic flux loops erupt in the solar atmosphere. Solar observations detect energetic particles and hard X-rays but cannot reveal the generating mechanism because the particle acceleration happens at a scale smaller than the observation resolution. Thus, details of the cross-scale physics that explain the generation of energetic particles and hard X-rays remain a mystery. Here, we present observations from a laboratory experiment that simulates solar coronal loop physics. Transient, localized 7.6-keV X-ray bursts and a several-kilovolt voltage spike are observed in braided magnetic flux ropes of a 2-eV plasma when the braid strand radius is choked down to be at the kinetic scale by either magnetohydrodynamic (MHD) kink or magnetic Rayleigh–Taylor instabilities. This sequence of observations reveals a cross-scale coupling from MHD to non-MHD physics that is likely responsible for generating solar energetic particles and X-ray bursts. All the essential components of this mechanism have been separately observed in the solar corona.
© The Author(s), under exclusive licence to Springer Nature Limited 2023. This material is based upon work supported by the NSF (Awards 1914599 and 2105492 to P.M.B.). The X-ray detector used in this work was developed with support from the USDOE ARPA-E (Grant DE-AR0001159 to P.M.B.). Contributions. Y.Z. designed the braided loop experiment from the suggestions and guidance of P.M.B. S.P. built the X-ray camera from the suggestions and guidance of P.M.B. Y.Z. and S.P. performed the experiment. The interpretation of the results was done jointly by all authors. Y.Z. drafted the manuscript. All authors revised the manuscript together. Data availability. The experimental data reported here were generated by the Caltech Solar Loop Experiment and have been uploaded to https://data.caltech.edu/records/rcrh7-7ps89. Code availability. Information about LTspice circuit simulation software is available at https://www.analogue.com/en/design-centre/design-tools-and-calculators/ltspice-simulator.html. The authors declare no competing interests.
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