Picoflare jets power the solar wind emerging from a coronal hole on the Sun

Chitta, L. P.; Zhukov, A. N.; Berghmans, D.; Peter, H.; Parenti, S.; Mandal, S.; Aznar Cuadrado, R.; Schühle, U.; Teriaca, L.; Auchère, F.; Barczynski, K.; Buchlin, É.; Harra, L.; Kraaikamp, E.; Long, D. M.; Rodriguez, L.; Schwanitz, C.; Smith, P. J.; Verbeeck, C.; Seaton, D. B.

doi:10.1126/science.ade5801

“…Wang et al (2022) identified 88 flux cancellation events associated with Hα spicules, out of which seven events are associated with EUV jets/spicules. Based on the statistics of the observed jets (that are on scales of a few hundred kilometers), Raouafi et al (2023) argued that they can provide sufficient mass and energy flux into the corona to explain the solar wind (see also Chitta et al 2023b). We therefore propose that such jets are due to small-scale flux cancellation reconnection driven by photospheric flux cancellation on granular scales.…”

Section: Introductionmentioning

confidence: 86%

Coronal Heating and Solar Wind Generation by Flux Cancellation Reconnection

Pontin,

Priest,

Chitta

et al. 2023

ApJ

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In this paper, we propose that flux cancellation on small granular scales (≲1000 km) ubiquitously drives reconnection at a multitude of sites in the low solar atmosphere, contributing to chromospheric/coronal heating and the generation of the solar wind. We analyze the energy conversion in these small-scale flux cancellation events using both analytical models and three-dimensional, resistive magnetohydrodynamic (MHD) simulations. The analytical models—in combination with the latest estimates of flux cancellation rates—allow us to estimate the energy release rates due to cancellation events, which are found to be on the order 106–107 erg cm−2 s−1, sufficient to heat the chromosphere and corona of the quiet Sun and active regions, and to power the solar wind. The MHD simulations confirm the conversion of energy in reconnecting current sheets, in a geometry representing a small-scale bipole being advected toward an intergranular lane. A ribbon-like jet of heated plasma that is accelerated upward could also escape the Sun as the solar wind in an open-field configuration. We conclude that through two phases of atmospheric energy release—precancellation and cancellation—the cancellation of photospheric magnetic flux fragments and the associated magnetic reconnection may provide a substantial energy and mass flux contribution to coronal heating and solar wind generation.

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“…The Solar Orbiter-observed picoflare jets of Chitta et al (2023) are much smaller still, with spatial scales of ∼few × 100 km, which is comparable to the widths of spicules. They estimate a lower limit of the kinetic energy to be ∼10 21 erg for the picoflare jets.…”

Section: Smaller Jetlike Featuresmentioning

confidence: 94%

“…Furthermore, they argue that the magnetic switchbacks, which are localized rotations in the solar wind magnetic field that are ubiquitously detected in near-Sun Parker Solar Probe (PSP) data, could also be a consequence of the magnetic reconnection events that produce the jetlets and solar wind and are built up and triggered by fine-scale flux cancelation. Chitta et al (2023), on the other hand, use Solar Orbiter data to conclude that there are even smaller-scale features, which they call "picoflare jets," with widths ∼100 km. These observations are of a coronal hole using Solar Orbiter's EUV High Resolution Imager (HRI EUV ) at 174 Å and were taken during a close approach of 0.332 au, where the images had a spatial resolution of about 237 km.…”

Section: Introductionmentioning

confidence: 99%

How Small-scale Jetlike Solar Events from Miniature Flux Rope Eruptions Might Produce the Solar Wind

Sterling,

Panesar,

Moore

2024

ApJ

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We consider small-scale jetlike events that might make the solar wind, as has been suggested in recent studies. We show that the events referred to as “coronal jets” and as “jetlets” both fall on a power-law distribution that also includes large-scale eruptions and spicule-sized features; all of the jetlike events could contribute to the solar wind. Based on imaging and magnetic field data, it is plausible that many or most of these events might form by the same mechanism: Magnetic flux cancelation produces small-scale flux ropes, often containing a cool-material minifilament. This minifilament/flux rope erupts and reconnects with adjacent open coronal field, along which “plasma jets” flow and contribute to the solar wind. The erupting flux ropes can contain twist that is transferred to the open field, and these become Alfvénic pulses that form magnetic switchbacks, providing an intrinsic connection between switchbacks and the production of the solar wind.

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“…The purpose of this work is to establish a theoretical scaling law for  M w (Schröder & Cuntz 2005;Cranmer & Saar 2011;Suzuki et al 2013;Suzuki 2018;Chebly et al 2023) that aligns with both solar and stellar observations. Solar wind models generally rely on either Alfvén-wave acceleration (Ofman & Davila 1995, 1998Matthaeus et al 1999;Dmitruk et al 2002;Ofman 2004;Suzuki & Inutsuka 2005;Verdini & Velli 2007;Verdini et al 2010;Perez & Chandran 2013;van der Holst et al 2014;van Ballegooijen & Asgari-Targhi 2016;Usmanov et al 2018;Shoda et al 2019;Réville et al 2020;Matsumoto 2021;Schleich et al 2023) or loop-opening acceleration (Fisk et al 1999;Fisk 2003;Rappazzo et al 2012;Lionello et al 2016;Chitta et al 2023aChitta et al , 2023bBale et al 2023;Drake et al 2023;Kumar et al 2023;Raouafi et al 2023). Recent observations of magnetic switchbacks (Bale et al 2019;Kasper et al 2019;Bale et al 2021;Telloni et al 2022) appear to support the loop-opening scenario (Fisk & Kasper 2020;Tenerani et al 2020;Zank et al 2020;D...…”

Section: Introductionmentioning

confidence: 99%

Formulating Mass-loss Rates for Sun-like Stars: A Hybrid Model Approach

Shoda,

Cranmer,

Toriumi

2023

ApJ

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We observe an enhanced stellar wind mass-loss rate from low-mass stars exhibiting higher X-ray flux. This trend, however, does not align with the Sun, where no evident correlation between X-ray flux and mass-loss rate is present. To reconcile these observations, we propose a hybrid model for the stellar wind from solar-type stars, incorporating both Alfvén wave dynamics and flux emergence-driven interchange reconnection, an increasingly studied concept guided by the latest heliospheric observations. For establishing a mass-loss rate scaling law, we perform a series of magnetohydrodynamic simulations across varied magnetic activities. Through a parameter survey concerning the surface (unsigned) magnetic flux (Φsurf) and the open-to-surface magnetic flux ratio (ξ open = Φopen/Φsurf), we derive a scaling law of the mass-loss rate given by M ̇ w / M ̇ w , ⊙ = Φ surf / Φ ⊙ surf 0.52 ξ open / ξ ⊙ open 0.86 , where M ̇ w , ⊙ = 2.0 × 10 − 14 M ⊙ yr − 1 , Φ ⊙ surf = 3.0 × 10 23 Mx , and ξ ⊙ open = 0.2 . By comparing cases with and without flux emergence, we find that the increase in the mass-loss rate with the surface magnetic flux can be attributed to the influence of flux emergence. Our scaling law demonstrates an agreement with solar wind observations spanning 40 yr, exhibiting superior performance when compared to X-ray-based estimations. Our findings suggest that flux emergence may play a significant role in the stellar winds of low-mass stars, particularly those originating from magnetically active stars.

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Picoflare jets power the solar wind emerging from a coronal hole on the Sun

Cited by 19 publications

References 74 publications

Coronal Heating and Solar Wind Generation by Flux Cancellation Reconnection

Coronal Heating and Solar Wind Generation by Flux Cancellation Reconnection

How Small-scale Jetlike Solar Events from Miniature Flux Rope Eruptions Might Produce the Solar Wind

Formulating Mass-loss Rates for Sun-like Stars: A Hybrid Model Approach

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