[GEM] THE GEM MESSENGER, Volume 28, Number 48

Wed Oct 10 16:57:13 PDT 2018

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     THE GEM MESSENGER
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Volume 28, Number 48
Oct.10,2018

Announcement submission website: http://aten.igpp.ucla.edu/gem/messenger_form/

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Table of Contents

1. GEM Testing Proposed Links between Mesoscale Auroral and Polar Cap Dynamics and Substorms Focus Group: 2018 Workshop Report

2. Postdoctoral Position in Atmospheric and Space Physics at Clemson University

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1. GEM Testing Proposed Links between Mesoscale Auroral and Polar Cap Dynamics and Substorms Focus Group: 2018 Workshop Report
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From: Co-chairs: Kyle Murphy (kyle.r.murphy at nasa.gov), Toshi Nishimura, Emma Spanswick, and Jian Yang (substorms) and Christine Gabrielse, Matina Gkioulidou, Slava Merkin, Drew Turner, and David Malaspina (dipolarizations)

The Testing Proposed Links between Mesoscale Auroral and Polar Cap Dynamics and Substorms Focus Group was apart of three joint sessions at 2018 GEM; one with the ULF wave Modelling, Effects and Applications Focus Group and the Magnetotail Dipolarization and its Effects on the Inner Magnetosphere Focus Group; and two with the Magnetotail Dipolarization and its Effects on the Inner Magnetosphere Focus Group. This report covers the two joint sessions with the Magnetotail Dipolarization and its Effects on the Inner Magnetosphere Focus Group. The first of the joint sessions was dedicated to challenge events and presentations from both an observational and modelling perspective. The second session was dedicated to contributed talks focusing on dipolarizations, fast flows, modelling, tail modes, and the effects these processes have on the inner magnetosphere.   

1. Joint Session – Challenge Events. 

The focus of this session was to compare and contrast observations of storm-time substorms, isolated substorms, and steady magnetospheric convection (SMC), and the effects that these tail modes have on the inner magnetosphere. Four events where chosen for initial studies: (1) an SMC event between 2013 August 24-28, storm time substorms on (2) 2016-09-04 ~7:20 UT and (3) 2016-09-27 ~04:30 UT, and (4) an isolated substorm on 2017-02-02 ~4 UT. An overview of the events can be found at goo.gl/zCeiAa. Ground-based, in situ, and model results were presented including, all sky imagers, riometers, ground-based magnetometers, in situ plasma and wave measurements and global MHD simulations. Christine Gabrielse and Toshi Nishimura presented detailed observations from the THEMIS probes, ASI, and ground-based riometers. Drew Turner presented observations from MMS and the Van Allen Probes. Amy Keese presented observations from TWINS. Lauren Blum presented EMIC wave observations from the Van Allen probes. Colin Komar present initial global MHD results from the Solar Wind Modeling Framework for each challenge event. Kyle Murphy presented injection signature from the LANL spacecraft and Anna DeJong presented ground-based observations regarding the steady magnetospheric convection event. 

One of the major highlights from the session was discussion regarding steady magnetospheric convection: how it was manifested in in situ, geosynchronous, and ground-based data, how steady/stable steady magnetospheric convection needs to be considered as an SMC event, and whether or not SMCs can be accurately defined without global auroral imaging. Christine Gabrielse showed that during the SMC event, there was almost one-to-one correlation between AE enhancements and riometer observations of precipitating electrons from injection. (This was part of what led to the discussion regarding SMC definition. If AE varied that much, was it really an SMC?) Anna DeJong argued that the event was not truly an SMC for this reason. Toshi Nishimura correlated injections observed at MMS with THEMIS all-sky-imager observations of auroral streamers. Drew Turner also presented initial observations from MMS that elude to direct loss of tail injected plasma to the dawn-flank magnetopause. Lauren Blum showed evidence of EMIC wave activity during storm-time substorms but saw little activity during the SMC and isolated substorms. At geosynchronous Kyle Murphy showed clear differences between the SMC event and storm-time substorms – the SMC event showing little injection activity while the storm-time substorms showed both numerous and intense injections. Future sessions will narrow in on some of these highlights for additional discussion. 

2. Contributed Talks

Sarah Vines presented observations of field aligned currents from AMPERE and tail flows from MMS during an interval of steady magnetospheric convection on 2017 June 21-22. Sarah demonstrated that during the SMC interval there were sustained Birkeland currents but no clear identification of major onsets in the night side field aligned currents; MMS however showed clear Earthward flows and dipolarizations between -15 - -25 RE, indicating that reconnection was occurring in the more distant tail during this event but without the development of any major nightside FAC onsets. Grant Stephens presented new results from the newest iteration of the Tsyganenko empirical magnetic field model which ingests ground-based magnetometer data (AE and Dst) to aid in modelling of the global magnetic field. Grant used the new empirical model to model two of the Joint Focus Groups challenge events, a storm-time substorm and an isolated substorm and showed that both events show a characteristic thinning of the plasma sheet during the growth phase and an enhancement in the ring current during the expansion phase. Slava Merkin presented a new framework to incorporate the ring current into global MHD simulations. Using the new TS07d empirical magnetic field model a derived ring current pressure is coupled to the Gamera global MHD model, allowing for a more complete global simulation. Sasha Ukhorskiy presented results from the coupled LFM Chimp global magnetosphere model which uses LFM magnetic field to drive test particles in the Earth’s magnetosphere. New results elucidate the motion of particles in the magnetosphere including where and how they are lost. Anna DeJong presented a detailed case study contrasting ionospheric conductance during an interval of steady magnetospheric convection and a substorm. Anna showed that ionospheric conductance before and during the events play a key role in whether a substorm subsequently develops into steady magnetospheric convection following onset. Shin Ohtani discussed poleward boundary intensifications and their relation to distant tail reconnection suggesting that they may not be ionospheric manifestation of tail reconnection. Bea Gallardo-Lacourt presented a correlative study of polar cap boundary identification using DMSP and redline auroral images to develop a new method to statistically and routinely identify the polar cap boundary using optical data.

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2. Postdoctoral Position in Atmospheric and Space Physics at Clemson University
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From: Xian Lu (xianl at clemson.edu)

The Department of Physics and Astronomy at Clemson University invites applications for a postdoctoral position in atmospheric and space physics under the mentorship of assistant professor Xian Lu. A successful applicant will pursue research on Earth’s middle and upper atmosphere and/or ionosphere broadly aligned with Prof. Lu’s research interests that can be found at http://xianl.people.clemson.edu/index.html. 

The position is suitable for applicant who held a PhD in atmospheric science, space physics, fluid dynamics, applied math, or another relevant field for no more than five years. Applicants with the research experiences in the numerical modeling and/or data analysis are preferred.

The anticipated start date is February 2019; some flexibility is possible on the specific time of arrival. All applications received by January 1, 2019 are guaranteed full consideration; however, applications will continue to be reviewed until the position is filled. The initial appointment will be for one year with the option for yearly renewal for up to three years based on performance and availability of funding.

Application Instructions

The applicants should submit a curriculum vitae, list of publications, dissertation abstract, a clearly articulated research statement of no more than 5 pages excluding references, and the names and contact data of three references as a single PDF via Interfolio (apply.interfolio.com/56345). Reference letters will only be sought for short-listed candidates.

For further information, contact Prof. Lu at xianl at clemson.edu or (864) 656-4204.

Clemson University is an Affirmative Action/Equal Opportunity employer and does not discriminate against any individual or group of individuals on the basis of age, color, disability, gender, national origin, race, religion, sexual orientation, veteran status or genetic information.

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