{"id":2,"date":"2026-07-13T11:37:22","date_gmt":"2026-07-13T11:37:22","guid":{"rendered":"https:\/\/teams.issibern.ch\/superhaloenigma\/?page_id=2"},"modified":"2026-07-17T11:13:47","modified_gmt":"2026-07-17T11:13:47","slug":"home","status":"publish","type":"page","link":"https:\/\/teams.issibern.ch\/superhaloenigma\/","title":{"rendered":"Home"},"content":{"rendered":"\r\n<p class=\"wp-block-paragraph\"><strong><span style=\"font-size: 18pt\">An unsolved enigma<\/span><\/strong><\/p>\r\n<p style=\"font-weight: 400\">The space between the Sun and the planets is filled with the solar wind: a continuous stream of electrically charged particles flowing outward from the Sun. Its electrons are usually grouped into several populations according to their energy and direction of travel.<\/p>\r\n<p style=\"font-weight: 400\">Most belong to the low-energy core, which contains the great majority of solar-wind electrons. At higher energies, the halo forms a more diffuse population, while the strahl appears as a beam of electrons travelling mainly along the interplanetary magnetic field. Beyond these lies a much lower density and more energetic population: the <strong>electron superhalo<\/strong>, extending from a few keV to hundreds of keV.<\/p>\r\n<p style=\"font-weight: 400\">Superhalo electrons are detected even when the Sun is quiet, yet their origin remains unknown. They may be accelerated close to the Sun, energised as they travel through turbulent interplanetary space, or produced by a combination of processes. Understanding them is especially important because they may provide the \u201cseed\u201d population from which electrons are later accelerated to much higher energies.<\/p>\r\n<p style=\"font-weight: 400\">Our ISSI international team brings together experts in in-situ and remote spacecraft observations, theory and numerical modelling. We will combine measurements from Solar Orbiter, Parker Solar Probe, Wind and STEREO to study the superhalo from very close to the Sun out to Earth\u2019s orbit. We aim to answer one central question:<\/p>\r\n<p style=\"font-weight: 400\"><span style=\"font-size: 14pt\"><strong>What is the origin of the electron superhalo, and how does it evolve as it travels through the inner Solar System?<\/strong><\/span><\/p>\r\n<p style=\"font-weight: 400\"><strong>Why it matters. <\/strong>Understanding the superhalo is important for two closely connected reasons. First, it provides a window into how the Sun energises particles and how energetic electrons are produced and transported throughout the heliosphere. Second, it represents the crucial starting population for further electron acceleration to much higher energies, an initial condition that remains poorly constrained in current particle acceleration theories. Because similar processes operate in distant astrophysical systems that cannot be investigated in situ, studying the superhalo in our own cosmic neighbourhood can also help us understand how energetic particles are generated across the Universe.<\/p>\r\n<p style=\"font-weight: 400\"><strong>Our goal. <\/strong>Our team will deliver the first comprehensive characterisation of the electron superhalo, revealing how it forms, what controls its properties during quiet and active solar conditions, and how it changes as it travels through the inner heliosphere.<\/p>\r\n","protected":false},"excerpt":{"rendered":"<p>An unsolved enigma The space between the Sun and the planets is filled with the solar wind: a continuous stream of electrically charged particles flowing outward from the Sun. Its electrons are usually grouped into several populations according to their energy and direction of travel. Most belong to the low-energy core, which contains the great [&hellip;]<\/p>\n","protected":false},"author":204,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-2","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/teams.issibern.ch\/superhaloenigma\/wp-json\/wp\/v2\/pages\/2","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/teams.issibern.ch\/superhaloenigma\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/teams.issibern.ch\/superhaloenigma\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/teams.issibern.ch\/superhaloenigma\/wp-json\/wp\/v2\/users\/204"}],"replies":[{"embeddable":true,"href":"https:\/\/teams.issibern.ch\/superhaloenigma\/wp-json\/wp\/v2\/comments?post=2"}],"version-history":[{"count":3,"href":"https:\/\/teams.issibern.ch\/superhaloenigma\/wp-json\/wp\/v2\/pages\/2\/revisions"}],"predecessor-version":[{"id":16,"href":"https:\/\/teams.issibern.ch\/superhaloenigma\/wp-json\/wp\/v2\/pages\/2\/revisions\/16"}],"wp:attachment":[{"href":"https:\/\/teams.issibern.ch\/superhaloenigma\/wp-json\/wp\/v2\/media?parent=2"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}