Peristaltic Flow Model Proposed as Mechanism for Solar Spicules
Researchers have developed an analytical model suggesting that peristaltic transport driven by magnetosonic waves in compressible magnetohydrodynamics (MHD) could explain the formation of solar spicules. Solar spicules are narrow, jet-like structures in the Sun's chromosphere whose origin has long been debated. The model predicts a mass flux roughly 100 times that of the solar wind, offering a testable observational signature that could help resolve a longstanding puzzle in solar physics.
A new preprint submitted to arXiv proposes that peristaltic flow within compressible, ideal MHD provides a viable physical mechanism for generating solar spicules — the ubiquitous, collimated plasma jets observed in the solar chromosphere. Using a small-amplitude perturbation expansion under a thin-tube, long-wavelength approximation with a uniform axial background magnetic field, the authors derive the net time-averaged volumetric flow rate driven by the nonlinear coupling between thermodynamic pressure variations and magnetic tension stresses. Under equipartition conditions (plasma beta ~1, where sound speed equals Alfvén speed) and observationally realistic supersonic Mach numbers of approximately 2–10, the model yields a strongly directional upward flow consistent with spicular behavior. For wave amplitudes of roughly 10%, the estimated local mass flux is approximately 100 times that of the solar wind. The authors also propose a specific observational test: individual spicular jets should be directly preceded by magnetosonic wave trains visible as localized intensity modulations in chromospheric imaging. Beyond solar physics, the framework may have implications for laboratory plasma pinch devices, stellar winds, and magnetized accretion disks.
What's missing
The study is a preprint that has not yet undergone peer review, so its analytical results and assumptions remain unvalidated by independent referees. The model relies on idealized conditions (ideal MHD, thin-tube approximation, uniform background field) that may not fully capture the complexity of the real solar chromosphere. The authors do not address competing spicule formation mechanisms (e.g., ion-neutral coupling, reconnection-driven models) or quantitatively compare predicted observational signatures against existing high-resolution chromospheric datasets such as those from IRIS or SST.
What different sources said
- arXiv physicsCenter
Peristaltic Flow in Compressible, Ideal Magnetohydrodynamics: A Mechanism For Solar Spicules
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