Browsing by Author "Matteini L."

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    Magnetic Switchback Formation: A Review of Proposed Mechanisms
    (2026-06-01) Wyper P.F.; Squire J.; Pariat E.; Agapitov O.V.; Drake J.F.; Magyar N.; Matthaeus W.H.; Matteini L.; Ruffolo D.; Réville V.; Shi C.; Shoda M.; Swisdak M.; Velli M.; Akhavan-Tafti M.; Gannouni B.; Lionello R.; Madjarska M.S.; Owens M.J.; Raouafi N.E.; Sterling A.C.; Tripathi D.; Wyper P.F.; Mahidol University
    Magnetic switchbacks are large amplitude deflections of the magnetic field within the solar wind. They are Alfvénic in character and so are associated with a spike in velocity and a generally small variation in local plasma density. Early orbits of Parker Solar Probe revealed that the solar wind near the Sun is dominated by these structures, and therefore, they may be playing an important role in the energy budget and acceleration of the young solar wind. In this review, we present an overview of different mechanisms that have been proposed for how switchbacks could be formed. We group the mechanisms by whether they predominantly act in the low solar atmosphere or within the solar wind (in situ). We focus on mechanisms that can create reversals of the ambient magnetic field direction and, thus, account for the most extreme perturbations. The general consensus is that mechanisms in the lower solar atmosphere do not form such reversals on their own but provide the seed perturbations, flows, or particle beams necessary for in situ mechanisms to create switchbacks within the solar wind. Switchback observations thus likely contain an imprint of the coronal source of the seed perturbation or flow, which is evolved further locally by one of several plausible in situ mechanisms. We discuss the strengths and weaknesses of each mechanism and outline future observational and theoretical tests that could help differentiate between them.
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    Properties of Magnetic Switchbacks in the Near-Sun Solar Wind
    (2026-01-01) Badman S.T.; Fargette N.; Matteini L.; Agapitov O.V.; Akhavan-Tafti M.; Bale S.D.; Bharati Das S.; Bizien N.; Bowen T.A.; Dudok de Wit T.; Froment C.; Horbury T.; Huang J.; Jagarlamudi V.K.; Larosa A.; Madjarska M.S.; Panasenco O.; Pariat E.; Raouafi N.E.; Rouillard A.P.; Ruffolo D.; Sioulas N.; Soni S.L.; Sorriso-Valvo L.; Suen G.H.H.; Velli M.; Verniero J.; Badman S.T.; Mahidol University
    Magnetic switchbacks are fluctuations in the solar wind in which the interplanetary magnetic field sharply deflects away from its background direction so as to create folds in magnetic field lines while remaining of roughly constant magnitude. The magnetic field and velocity fluctuations are extremely well correlated in a way corresponding to Alfvénic fluctuations propagating away from the Sun. For a background field which is nearly radial this causes an outwardly propagating jet to form. Switchbacks and their characteristic velocity jets have recently been observed to be nearly ubiquitous by Parker Solar Probe with in situ measurements in the inner heliosphere within 0.3 AU. Their prevalence, substantial energy content, and potentially fundamental role in the dynamics of the outer corona and solar wind motivate the significant research efforts into their understanding. Here we review the in situ measurements of these structures (primarily by Parker Solar Probe). We discuss how they are identified and measured, and present an overview of the primary observational properties of these structures, both in terms of individual switchbacks and their collective arrangement into “patches”. We identify both properties for which there is a strong consensus and those that have limited or qualified support and require further investigation. We identify and collate several open questions and recommendations for future studies.