The Sun\u2019s corona is like a vast ocean of invisible magnetic ropes. Along these ropes, waves ripple constantly, making the structures sway back and forth, almost like branches in the wind.<\/p>\n
The most common disturbances are transverse magnetohydrodynamic (MHD) waves: Alfv\u00e9nic or kink waves. In contrast to the forward-moving waves of the ocean, these waves push across, spacing out vertical oscillations in the magnetic ropes as they move outward.<\/p>\n
This motion is observable spectroscopically through Doppler shifts: plasma moving toward the observer results in a redshift, and plasma moving away<\/a> from the observer produces a blueshift. That pattern resembles dancers dancing in and out of harmony.<\/p>\n But one important question is: can these transverse waves actually change the shape of spectral lines, distorting them from their usual smooth, bell-shaped (i.e., Gaussian) profile? It would be like detecting a hidden inflection in our own Sun\u2019s spectrum, yet no such evidence can be found!<\/p>\n The largest turbulence simulation reveals the energy flow in astrophysical plasmas<\/a><\/p>\n Past solar observations have often shown a spectral line \u201cblue tilt\u201d, interpreted as imprints of plasma jets<\/a> or mass flows moving up along the magnetic structures.<\/p>\n Transverse waves are widely understood to be nearly incompressible and thus neglected in their contributions to spectral line shapes.<\/p>\n A new study by researchers at ARIES (Nainital) and IIT Delhi used advanced 3D simulations to investigate this scenario. They simulated a coronal medium with varying plasma densities, initiated upward-propagating transverse waves, and calculated the expected emission signatures in the Fe XIII 10749 \u00c5 spectral line, which is frequently observed in the corona.<\/p>\n The simulations showed that, across the Sun\u2019s magnetic plumes, plasma motions do not remain uniform as transverse waves propagate. Rather, the inhomogeneities in density then break up the wave into structures of finer scales, as threads are unspooled into turbulence.<\/p>\n A new view of small\u00a0sun\u00a0structures<\/a><\/p>\n Since the corona is optically thin, these intricately intertwined motions overlap along the line of sight. Regions move at different speeds, and the composition of their signals gives rise to deviations from perfect symmetry in the line profile, resulting in oscillating blue- and red-shifted asymmetries both with time and with height along the path of advance.<\/p>\n The study suggests that flickering asymmetries in coronal light are an inherent result of such transverse waves. When such waves encounter an inhomogeneous plasma, turbulence superposes velocities along the line of sight, distorting spectral lines.<\/p>\n Such distortions can be substantial (up to 20% of the line peak intensity) and persist with apparent velocities of 30\u201340 km\/s, where their red-blue flickering pattern propagates outward at the same speed as the transverse wave.<\/p>\n The authors said, \u201cThese asymmetries move with the transverse waves, and at DKIST resolution, similar signatures can be seen. Our work indicates that the asymmetries in spectral lines can be used as a unique diagnostic of uniturbulence excited by transverse waves.\u201d<\/p>\n Journal Reference:<\/p>\n Ambika Saxena, Vaibhav Pant, Tom Van Doorsselaere, M. Saleem Khan. Study of Asymmetries in Spectral Lines Caused by the Transverse Waves Propagating in the Corona of the Sun. The Astrophysical Journal. DOI 10.3847\/1538-4357\/ae2482<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"The Sun\u2019s corona is like a vast ocean of invisible magnetic ropes. Along these ropes, waves ripple constantly,…\n","protected":false},"author":2,"featured_media":459973,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[127920,61,60,82,7305,19451],"class_list":["post-459972","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-corona","tag-ie","tag-ireland","tag-science","tag-sun","tag-suns-atmosphere"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/459972","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/comments?post=459972"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/459972\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media\/459973"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media?parent=459972"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/categories?post=459972"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/tags?post=459972"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}