Paper

{
  "raw_xml": "<entry>\n    <id>http://arxiv.org/abs/2603.21885v1</id>\n    <title>On the Constraints and Observational Manifestations of Failed Solar Eruptions in Toroidal Magnetic Cage</title>\n    <updated>2026-03-23T12:13:52Z</updated>\n    <link href='https://arxiv.org/abs/2603.21885v1' rel='alternate' type='text/html'/>\n    <link href='https://arxiv.org/pdf/2603.21885v1' rel='related' title='pdf' type='application/pdf'/>\n    <summary>Observations show that many solar eruptions remain confined within strong overlying magnetic fields, forming a so-called magnetic cage. While confinement by poloidal overlying fields has been widely investigated, the role of strong external toroidal fields remains unclear. Using three-dimensional magnetohydrodynamic simulations, we study confined eruptions in a toroidal magnetic cage, focusing on the interplay between the Lorentz force and magnetic reconnection, and their observational signatures. We further employ a guiding-center test-particle approach to synthesize hard X-ray emission for comparison between thermal and nonthermal responses. We find that overlying toroidal fields play a crucial role in confinement by generating strong return currents that produce a significant downward Lorentz force, suppressing flux rope ascent. At the same time, they induce large-angle rotation of the flux rope, leading to reconnection with overlying fields and eventual break-up. Synthetic EUV emission reveals multi-ribbon flares with highly sheared, globally cowboy-hat-like loop structures. Hard X-ray diagnostics show that thermal and nonthermal emissions are not co-spatial, with return currents acting as an efficient accelerator of energetic electrons. These results demonstrate that toroidal-field-induced forces govern both the confinement and rotation of erupting flux ropes, providing an explanation for failed eruptions even under torus-unstable conditions. These results suggest that the morphology and shearing angle of flare loops are the useful diagnostics for distinguishing confined from eruptive events.</summary>\n    <category scheme='http://arxiv.org/schemas/atom' term='astro-ph.SR'/>\n    <published>2026-03-23T12:13:52Z</published>\n    <arxiv:comment>24 pages, 22 figures, accepted for publication in A&amp;A</arxiv:comment>\n    <arxiv:primary_category term='astro-ph.SR'/>\n    <author>\n      <name>Jinhan Guo</name>\n    </author>\n    <author>\n      <name>Y. Guo</name>\n    </author>\n    <author>\n      <name>H. Wu</name>\n    </author>\n    <author>\n      <name>B. Schmieder</name>\n    </author>\n    <author>\n      <name>P. Démoulin</name>\n    </author>\n    <author>\n      <name>Y. W. Ni</name>\n    </author>\n    <author>\n      <name>C. Wang</name>\n    </author>\n    <author>\n      <name>S. Poedts</name>\n    </author>\n    <author>\n      <name>T. Li</name>\n    </author>\n    <author>\n      <name>Wensi Wang</name>\n    </author>\n    <author>\n      <name>Y. H. Zhou</name>\n    </author>\n    <author>\n      <name>P. F. Chen</name>\n    </author>\n  </entry>"
}