Conductance in the Aurora: Inﬂuence of Magnetospheric Contributors

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M o d e r n T r e n d s i n S p a c e W e a t h e r P r e d i c t i o n Conductance in the Aurora: Influence of Magnetospheric Contributors A g n i t M u k h o p a d h y a y1 , D a n i e l W e l l i n g 1 , 2 , M e g h a n B u r l e i g h 1

K e y Q u e s t i o n
Can accurate estimation of the ionospheric conductivity in the auroral region help improve our space weather predictions?
How do we predict Space Weather?Space Weather can be predicted using observational and physics-based tools.Most commonly used predictive tool are global magnetohydrodynamic (MHD) models 5,8,10 .
What science problems affect predictions?One of the major issues with global models is the inaccurate prediction of the ionospheric conductance, which causes underprediction of storm-time indices 9 .

I N T R O D U C T I O N & S C I E N T I F I C B A C K G R O U N D
What are we changing?We propose to improve models used to predict the auroral conductance in MHD, and replace them with more physics to capture the precipitative processes more accurately.
How do we know predictions are accurate?Prediction efficiency of a given model is tested based on the accuracy of prediction of the timevarying magnetic field on the ground (dB/dt).Based on skill scores, a model's accuracy is defined 4 .
The impact of the ionospheric conductance on our space weather results are significant enough to cause physical as well as predictive improvements.
M-I Coupling in the SWMF (Legacy Model) SWMF allows passage of field aligned currents (FACs) onto a 2D ionosphere to apply Ohm's Law in order to estimate the electric potential in the ionosphere.For this to work, the ionospheric conductance in the aurora is assumed dependent on FACs.

Conductance Model for Extreme Events (CMEE)
The original empirical model relating auroral conductance with FACs was based on one month of AMIE data.We improved on this work to develop another empirical model that uses one year of AMIE data, choosing the year of 2003 to include extreme space weather activities in our dataset.

MAGNIT Physics-Based Conductance Model
Using elementary kinetic theory, we derive the diffuse and discrete particle flux and energy flux for a Maxwell-Boltzmann distribution.The total energy flux divided by the particle flux gives us the average energy.Using the average energy and the energy flux, we derive the conductance using the relation from [11].

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, A a r o n R i d l e y 1 , M i c h a e l L i e m o h n 1 , B r i a n A n d e r s o n 3 , J e s p e r G j e r l o e v Climate and Space Sciences and Engineering, University of Michigan; 2 Department of Physics, University of Texas at Arlington; 3 Applied Physics Lab, Johns Hopkins University A C K N O W L E D G M E N T S Sincere thanks to Dr. Shasha Zou, Dr. Doga can su Ozturk, Dr. Tuija Pulkkinen, Dr. James Slavin, Ms. Abigail Azari, Mr. Brian Swiger, Mr. Alexander Shane, Mr. Austin Glass, Ms. Camilla Harris, Mr. Tong Shi, Mr. Christopher Bert, Dr. Natalia Ganjushkina, Dr. Gabor Toth & Prof. Tamas Gombosi for their insights.Additionally, we would like to thank the NASA NESSF/FINESST Program, NSF PREEVENTS Program & the Los Alamos National Laboratory LDRD Program for sponsoring this work.
Flux Calculations Based on Pulkkinen et al. [2013] study Galaxy 15 Event April 5, 2010 10:17:00 UT Upper plots show qualitative comparison of Dst and CPCP, while left dial plots show qualitative comparison of conductance from the old empirical model, new empirical model and AMIE.Galaxy 15 Event (SWPC Event 5) April 5, 2010 10:40:00 UT Upper plots show comparison of average energy and energy flux with DMSP F16 observations against MAGNIT precipitation estimates.The precipitation is converted into conductance using the Robinson Relation [11].Plots on the left show CPCP, Integrated FACs and Sym-H comparisons for MAGNIT results along with the RLM and CMEE results against observations from SuperDARN, AMIE, AMPERE and Kyoto Observatory.c l u s i o n s P A S T F U T U R E Additional Science Questions Auroral Oval (AO) Adjustment In order to place the auroral oval accurately, an artificial adjustment function based on upward FACs is used to enhance the conductance in higher latitudinal regions.AO adjustment improves prediction.S A 4 1 B -3 1 6 9 C o n t a c t : a g n i t m @ u m i c h .e d u Two-Way Coupling to GITM Conductance Input from the Global Ionosphere Thermosphere Model (GITM) will help us get realistic ionospheric dynamics.[See Burleigh et al. 2019, Paper No. SA41B-3168]