{"id":10152,"date":"2025-06-13T10:03:14","date_gmt":"2025-06-13T01:03:14","guid":{"rendered":"https:\/\/unit.nifs.ac.jp\/research\/?post_type=news&#038;p=10152"},"modified":"2025-12-24T09:57:20","modified_gmt":"2025-12-24T00:57:20","slug":"news-10152","status":"publish","type":"news","link":"https:\/\/unit.nifs.ac.jp\/research\/archives\/news\/news-10152","title":{"rendered":"\u8907\u5408\u5927\u57df\u30b7\u30df\u30e5\u30ec\u30fc\u30b7\u30e7\u30f3\u30e6\u30cb\u30c3\u30c8\u30bb\u30df\u30ca\u30fc\uff087\u67089\u65e5\uff09"},"content":{"rendered":"\n<p>[\u65e5\u6642]\u30002025\u5e74 7\u6708 9\u65e5(\u6c34) 15:00\u301c16:00<\/p>\n\n\n\n<div style=\"height:24px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p>[\u5834\u6240]\u3000\u6838\u878d\u5408\u79d1\u5b66\u7814\u7a76\u6240\u00a0\u30b7\u30df\u30e5\u30ec\u30fc\u30b7\u30e7\u30f3\u79d1\u5b66\u7814\u7a76\u68df1\u968e\u4f1a\u8b70\u5ba4\u00a0\uff0b\u00a0\u30aa\u30f3\u30e9\u30a4\u30f3\u4f75\u7528<\/p>\n\n\n\n<p>\uff08\u63a5\u7d9a\u60c5\u5831\u306f\u5225\u9014\u30e1\u30fc\u30eb\u306b\u3066\u3001\u53c2\u52a0\u7533\u8fbc\u30fb\u62db\u5f85\u3055\u308c\u305f\u65b9\u3078\u304a\u77e5\u3089\u305b\u3057\u307e\u3059\uff09<\/p>\n\n\n\n<div style=\"height:24px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p>[\u8b1b\u5e2b]\u3000Sharad K Yadav (Sardar Vallabhbhai National Institute of Technology (SVNIT), India)<\/p>\n\n\n\n<div style=\"height:24px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p>[\u8b1b\u6f14\u984c\u76ee]\u3000Magnetic Prandtl number dependent fluctuation spectra and intermittency in 3D Hall- magnetohydrodynamics (HMHD) plasma turbulence<\/p>\n\n\n\n<div style=\"height:24px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p>[\u8b1b\u6f14\u6982\u8981]<br>Hall- magnetohydrodynamics (HMHD) is a simplified fluid description of plasma that accounts the two-fluid e\ufb00ects to some extent. It include Hall term via generalized Ohm\u2019s law and reduces to magnetohydrodynamics (MHD) if <em>d<\/em><sub><em>i<\/em><\/sub> = 0 where <em>d<sub>i<\/sub><\/em> is the ion-inertial<br>length. Hall- MHD equations are employed in many space and laboratory plasma processes such as magnetic-reconnection processes, sub-Alfvenic plasma expansion and magnetic-field transport in plasma opening switches. Turbulence in the solar wind[1] is often studied using the Hall magnetohydrodynamics (HMHD) equations. In this work[2, 3], we mainly carry out extensive pseudospectral direct numerical simulations (DNSs) of decaying three-dimensional (3D) Hall magnetohydrodynamics (3D HMHD) plasma turbulence at three magnetic Prandtl numbers <em>Pr<sub>m<\/sub><\/em> = 0.1, 1.0 and 10.0. In our simulations, we find two different inertial regions &#8211; in the first inertial region <em>k<\/em> &lt; <em>k<sub>i<\/sub><\/em>(\u2261 1\/<em>d<sub>i<\/sub><\/em>), both the kinetic-energy and magnetic-energy spectra, <em>E<sub>u<\/sub><\/em>(<em>k<\/em>) and <em>E<sub>b<\/sub><\/em>(<em>k<\/em>), respectively, display power-law regions with an exponent that is consistent with Kolmogorov-type -5\/3 scaling, at all values of <em>Pr<sub>m<\/sub><\/em>. In the second inertial region <em>k<\/em> > <em>k<sub>i<\/sub><\/em>, the scaling of <em>E<sub>b<\/sub><\/em>(<em>k<\/em>) depends upon <em>Pr<sub>m<\/sub><\/em> , at <em>Pr<sub>m<\/sub><\/em> = 0.1, the spectral-scaling exponent is -17\/3, but for <em>Pr<sub>m<\/sub><\/em> = 1 and 10 this exponent is -11\/3. We then show theoretically that <em>E<sub>b<\/sub><\/em>(<em>k<\/em>)\u223c <em>k<\/em><sup>-2<\/sup><em>E<sub>u<\/sub><\/em>(<em>k<\/em>) for <em>Pr<sub>m<\/sub><\/em> \u226a 1 and <em>E<sub>b<\/sub><\/em>(<em>k<\/em>)\u223c <em>k<\/em><sup>2<\/sup><em>E<sub>u<\/sub><\/em>(<em>k<\/em>) for <em>Pr<sub>m<\/sub><\/em> \u226b 1; our DNS results are consistent with our theoretical predictions. Moreover, we also show that 3D HMHD turbulence shows signatures of intermittency that we uncover by analyzing the scale dependence of probability distribution functions of velocity- and magnetic-field increments, their structure functions, and their flatnesses as functions of <em>d<sub>i<\/sub><\/em> and <em>Pr<sub>m<\/sub><\/em>.<\/p>\n\n\n\n<div style=\"height:24px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p>[1] K. H. Kiyani, S. C. Chapman, Y. V. Khotyaintsev, M. W. dunlop and F. Sahraoui, Phys. Rev. Lett., 103, 075006 (2009).<br>[2] S. K. Yadav, H. Miura and R. Pandit, Phys. Fluids, 34, 095135 (2022)<br>[3] P. Patel, S. K. Yadav, H. Miura and R. Pandit, https:\/\/arxiv.org\/abs\/2505.09537 (May,2025)<\/p>\n\n\n\n<div style=\"height:24px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p>[\u304a\u554f\u5408\u305b] \u3000cg-sim<img decoding=\"async\" style=\"width: 80px\" src=\"https:\/\/unit.nifs.ac.jp\/research\/wp-content\/themes\/nifs-dev\/img\/img_mail.svg\" alt=\"\"><\/p>\n\n\n\n<div style=\"height:40px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<ul class=\"wp-block-list has-small-font-size\">\n<li>\u672c\u30bb\u30df\u30ca\u30fc\u306f\u6838\u878d\u5408\u79d1\u5b66\u7814\u7a76\u6240\u5171\u540c\u7814\u7a76\u306e\u4e00\u74b0\u3068\u3057\u3066\u958b\u50ac\u3057\u307e\u3059\u3002\u5171\u540c\u7814\u7a76\u306b\u53c2\u753b\u3055\u308c\u3066\u3044\u308b\u7814\u7a76\u8005\u30fb\u5b66\u751f\u306e\u65b9\u306f\u3069\u306a\u305f\u3067\u3082\u3054\u53c2\u52a0\u3044\u305f\u3060\u3051\u307e\u3059\u3002\u63a5\u7d9a\u60c5\u5831\u3084\u65c5\u8cbb\u652f\u7d66\u306b\u3064\u3044\u3066\u306f\u3001cg-sim <code><img decoding=\"async\" style=\"width: 60px\" src=\"https:\/\/unit.nifs.ac.jp\/research\/wp-content\/themes\/nifs-dev\/img\/img_mail.svg\" alt=\"\"><\/code>\u307e\u305f\u306f\u5404\u6240\u5185\u4e16\u8a71\u4eba\u306b\u304a\u554f\u5408\u305b\u304f\u3060\u3055\u3044\u3002<\/li>\n\n\n\n<li>\u5f53\u65e5\u3001\u53c2\u52a0\u8005\u540d\u7c3f\u3092\u4f5c\u6210\u3057\u307e\u3059\u3002\u540d\u7c3f\u306f\u6cd5\u306b\u57fa\u3065\u3044\u3066\u958b\u793a\u3055\u308c\u308b\u5834\u5408\u304c\u3042\u308a\u307e\u3059\u3002<\/li>\n<\/ul>\n","protected":false},"author":9,"featured_media":1986,"menu_order":0,"template":"","meta":{"_acf_changed":false,"footnotes":""},"ppma_author":[347],"class_list":["post-10152","news","type-news","status-publish","has-post-thumbnail","hentry"],"acf":[],"_links":{"self":[{"href":"https:\/\/unit.nifs.ac.jp\/research\/wp-json\/wp\/v2\/news\/10152","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/unit.nifs.ac.jp\/research\/wp-json\/wp\/v2\/news"}],"about":[{"href":"https:\/\/unit.nifs.ac.jp\/research\/wp-json\/wp\/v2\/types\/news"}],"author":[{"embeddable":true,"href":"https:\/\/unit.nifs.ac.jp\/research\/wp-json\/wp\/v2\/users\/9"}],"version-history":[{"count":4,"href":"https:\/\/unit.nifs.ac.jp\/research\/wp-json\/wp\/v2\/news\/10152\/revisions"}],"predecessor-version":[{"id":11046,"href":"https:\/\/unit.nifs.ac.jp\/research\/wp-json\/wp\/v2\/news\/10152\/revisions\/11046"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/unit.nifs.ac.jp\/research\/wp-json\/wp\/v2\/media\/1986"}],"wp:attachment":[{"href":"https:\/\/unit.nifs.ac.jp\/research\/wp-json\/wp\/v2\/media?parent=10152"}],"wp:term":[{"taxonomy":"author","embeddable":true,"href":"https:\/\/unit.nifs.ac.jp\/research\/wp-json\/wp\/v2\/ppma_author?post=10152"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}