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Message from the MIST mailing list. Dear MIST community, The next MIST online seminar will take place on Tuesday 01 December at 1100 - 1200. Please save the date in your diaries! Further details on the seminar are below, including the Zoom meeting link. Details on all upcoming seminars, as well as links to recorded past seminars can be found at https://www.mist.ac.uk/meetings/mist-online-seminars. All recorded seminars are available via the MIST YouTube channel (https://www.youtube.com/channel/UCWcYpHGNNOZ-SMpYG66fZDw/) so please like & subscribe! Seminar details Mike Lockwood (University of Reading) Title: Semi-annual and Universal Time variations in the magnetosphere Abstract: The semi-annual variation in space weather, with strong peaks in average geomagnetic activity and in the occurrence of storms around the two equinoxes, was first identified in observations by Broun in 1848. It was not explained until 125 years later when Russell and McPherron analysed the implications of two facts: (1) that magnetic reconnection in the Earth's dayside magnetopause depends on the interplanetary magnetic field (IMF) orientation relative to Earth's magnetic axis; and (2) the average orientation of the IMF is that it lies in the solar equatorial plane. The Russell-McPherron (R-M) effect is the geometric effect of the variable orientation of Earth's magnetic axis relative to the solar equatorial plane and has been hugely successful. It is, without doubt, at the core of the semi-annual variation in average geomagnetic activity levels and the occurrence of small and moderate storms. However, there are some important and unexplained anomalies. The R-M effect does not correctly predict the observed Universal Time (UT) variations, which indicate that Earth's magnetic dipole tilt angle towards and away from the Sun plays a role. A great many and diverse theories have been proposed to explain this but there is now strong evidence that only those invoking the joint effect of the dipole tilt and solar wind dynamic pressure on the geomagnetic tail are correct. Secondly, large geomagnetic storms are driven by strong out-of-ecliptic southward IMF, usually caused by Coronal Mass Ejections, whereas the R-M effect is based on the idea of close to in-ecliptic IMF. In these cases, contrary to the claims of the original paper, the R-M effect actually acts to decrease, rather than increase, the severity of the greatest storms at the equinoxes, which is not what is observed. In addition, best analysis of the coupling of power from the solar wind into the magnetosphere shows that the R-M effect is not working in quite the way that was originally envisaged. Explaining these anomalies is vital to our understanding of magnetospheric behaviour and the prediction of space weather phenomenon and this tutorial will discuss what is known, what are common misconceptions and what we still need to understand. Zoom details Zoom meeting link: https://zoom.us/j/91102553593<https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fzoom.us%2Fj%2F91102553593&data=04%7C01%7Cjasmine.k.sandhu%40NORTHUMBRIA.AC.UK%7Cfe294e6268f145a5ec7308d87fe34939%7Ce757cfdd1f354457af8f7c9c6b1437e3%7C0%7C1%7C637399961450885014%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=wOfdJuwDh3MeMU%2BtyVkaSG0zRw%2FDDGW3k3XwWzX8f1A%3D&reserved=0> Meeting ID: 911 0255 3593 The zoom link is supported by Aberystwyth University and Queen’s University Green Fund. Slido Q&A Join the Slido Q&A session during the seminar to post questions anonymously and vote on what questions you want to be asked! You can join via www.slido.com<http://www.slido.com> with the event code #17973, or follow this link: https://app.sli.do/event/ykfvgi09. If you have any questions, please do not hesitate to get in touch! Many thanks, Jasmine Kaur Sandhu On behalf of MIST Council ------- Dr. Jasmine Kaur Sandhu (she/her) Research Associate Northumbria University Newcastle upon Tyne NE1 8ST, UK This message is intended solely for the addressee and may contain confidential and/or legally privileged information. Any use, disclosure or reproduction without the sender’s explicit consent is unauthorised and may be unlawful. If you have received this message in error, please notify Northumbria University immediately and permanently delete it. Any views or opinions expressed in this message are solely those of the author and do not necessarily represent those of the University. Northumbria University email is provided by Microsoft Office365 and is hosted within the EEA, although some information may be replicated globally for backup purposes. The University cannot guarantee that this message or any attachment is virus free or has not been intercepted and/or amended. To send a message to the list, email [log in to unmask] or visit http://www.jiscmail.ac.uk/cgi-bin/webadmin?P1&L=mist MIST Web page is http://www.mist.ac.uk/