{"id":226005,"date":"2016-05-27T02:00:00","date_gmt":"2016-05-26T23:00:00","guid":{"rendered":"http:\/\/www.fyysika.ee\/?guid=e12a959a5d95a15812bcc24ac239333f"},"modified":"2016-05-27T02:00:00","modified_gmt":"2016-05-26T23:00:00","slug":"poynting-flux-in-the-neighbourhood-of-a-point-charge-in-arbitrary-motion-and-radiative-power-losses","status":"publish","type":"post","link":"https:\/\/www.fyysika.ee\/?p=226005","title":{"rendered":"Poynting flux in the neighbourhood of a point charge in arbitrary motion and radiative power losses"},"content":{"rendered":"<p>We examine the electromagnetic fields in the neighbourhood of a \u2018point charge\u2019 in arbitrary motion<br \/>\nand thereby determine the Poynting flux across a spherical surface of vanishingly small radius<br \/>\nsurrounding the charge. We show that the radiative power losses from a point charge turn out to be<br \/>\nproportional to the scalar product of the instantaneous velocity and the first time-derivative of<br \/>\nthe acceleration of the charge. This may seem to be discordant with the familiar Larmor formula<br \/>\nwhere the instantaneous power radiated from a charge is proportional to the square of acceleration.<br \/>\nHowever, it seems that the root cause of the discrepancy actually lies in Larmor\u2019s formula, which is<br \/>\nderived using the acceleration fields but without due consideration for the Poynting flux associated<br \/>\nwith the velocity-dependent self-fields \u2018co-moving\u2019 with the charge. Further, while deriving<br \/>\nLarmor\u2019s formula, one equates the Poynting flux through a surface at some later time to the<br \/>\nradiation loss by t&#8230;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>We examine the electromagnetic fields in the neighbourhood of a \u2018point charge\u2019 in arbitrary motion<br \/>\nand thereby determine the Poynting flux across a spherical surface of vanishingly small radius<br \/>\nsurrounding the charge. We show that the radiative p&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_genesis_hide_title":false,"_genesis_hide_breadcrumbs":false,"_genesis_hide_singular_image":false,"_genesis_hide_footer_widgets":false,"_genesis_custom_body_class":"","_genesis_custom_post_class":"","_genesis_layout":"","footnotes":""},"categories":[178],"tags":[],"class_list":{"0":"post-226005","1":"post","2":"type-post","3":"status-publish","4":"format-standard","6":"category-rss-fuusikaharidus","7":"entry"},"_links":{"self":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts\/226005","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=226005"}],"version-history":[{"count":0,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts\/226005\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=226005"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=226005"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=226005"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}