Date: 30 April 2024 Dataset Title: May 15 2005 Theta Aurora SWMF Simulation Data & Results Dataset Creators: Hill, Shannon C. Dataset Contact: Hill, Shannon C. shanhill@umich.edu Funding: University of Michigan Rackham Merit Fellowship Key Points: - We show first global MHD simulation event study that successfully produces a Joule heating signature that we identify as theta aurora - Simulation associates transpolar arc signatures with reconnection at the magnetospheric flank and in the distant magnetotail - The transpolar arc maps to a cross‐tail current disruption and field‐aligned current source region in a highly twisted magnetotail Research Overview: The light of the aurora observed in the Earth's atmosphere is a signature of magnetic processes in outer space. The Sun produces hot magnetized plasma that blows through the solar system like a wind. The Earth's magnetic field shields us from the harmful impacts of the Sun's magnetized plasma wind. The interaction between the Earth's magnetic field and the Sun's plasma wind causes the ring of auroral light we see in the polar regions. Sometimes the ring of auroral light grows a bar of auroral light across its center (over the Earth's magnetic poles), transforming the ring into a structure like the Greek letter theta. We call this the theta aurora. It is unknown what physical processes in the Earth's magnetic field create the theta aurora. In this study we show the first realistic simulation that uses solar wind driver conditions of an observed theta aurora event, and demonstrate that we can successfully produce the theta aurora structure in the simulation. We find that the theta aurora's center bar of auroral light comes from multiple regions in the vast Earth's magnetotail. This new result helps us better understand the dynamics of the Earth'sspace environment and better protect ourselves against the Sun's hazardous plasma wind effects. Methodology: The data are model output from Earth's magnetosphere simulations by the Space Weather Modeling Framework in the Geospace configuration run on the University of Michigan's Great Lakes HPC cluster. Date Coverage: 15 May 2005 00:20UT - 08:20 UT. This is the date coverage of the solar wind input from Wind satelite and the date coverage of the resulting simulation output. Instrument and/or Software specifications: Tecplot 360 2021 R2 was used to process the GM module simulation output (the 3D simulation results in the BATS-R-US domain). global_energetics python software (see zipped folder) used with Tecplot 360 2021 R2. Software needed: Tecplot 360 2021 R2 Python 3.9.0 python packages spacepy 0.5.0a0 swmfpy 2022.1 pytecplot 1.3.3 numpy 1.26.4 matplotlib 3.4.3 pandas 1.1.4 python software global_energetics (locally downloaded, see following section Files and Folders contained here) Files and folders contained here: theta_aurora_paper_figures_deepblue.py - Python file that includes multiple function definitions for processing and subsequently plotting the SWMF simulation data found in the SWMF_GM_output folder and the SWMF_IE_output folder and the SWMF simulation *.log files. The function defintions also use the IMF_WIND_shifted.dat file and the 20230320-19-54-supermag.csv file. The specific functions used for the final submission of the GRL paper that cites this data set are: theta_aurora_figure1_GRL_resubmit and theta_aurora_figure2_GRL_resubmit. global_energetics.zip - folder of locally developed python software by Dr. Austin Brenner at the University of Michigan used to interface with Tecplot via python. This package is called in theta_aurora_paper_figures_new.py with the line 'import global_energetics.extract.stream_tools as tools'. log_e20050515-002000.log - Output file from SWMF simulation that contains the simulation calculated SYM/H and the simulation calculated cross polar cap potential for each hemisphere for each minute of the simulation (00:20 UT to 08:20 UT 15 May 2005). This file is used with theta_aurora_paper_figures_new.py to plot the SYM/H comparison betweem simulation results and observations. geoindex_e20050515-002000.log - Output file from SWMF simulation that contains the simulation calculated AE, AL, and AU index for each minute of the simulation (00:20 UT to 08:20 UT 15 May 2005). This file is used with theta_aurora_paper_figures_new.py to plot the AL comparison between simulation results and observations. IMF_WIND_shifted.dat - The input file for the SWMF simulation. It contains the solar wind observations from the Wind satelite at L1. The input solar wind observations are shifted 20 minutes to account for propagation time between L1 and the magnetosphere bow shock at Earth. 20230320-19-54-supermag.csv - The supermag observations of the AL index and the SYM/H index (called SMR and SML by supermag) used to compare to the SWMF simulation calculations of the SYM/H and AL (found in the *.log files described above). The folders contain the simulation data from two separate simulation domains (IE and GM). - Folder SWMF_GM_output: 417 files (156.57 GB) with *.plt extension. Used with Tecplot software. Data output between 00:35 UT to 07:49 UT 15 May 2005. - Folder SWMF_IE_output: 481 files (5.54 GB) with *.idl extension. Used with spacepy.pybats.rim python package. Data output between 00:21 UT to 08:19 UT 15 May 2005. Related publication(s): Hill, S. C., Pulkkinen, T. I., Brenner, A., Al Shidi, Q., Mukhopadhyay, A., Kullen, A., et al. (2024). Magnetospheric sources of theta aurora: A case study comparing observations with SWMF global simulation. Geophysical Research Letters, 51, e2023GL108002. https://doi.org/10. 1029/2023GL108002 Use and Access: This data set is made available under a Creative Commons Attribution-NonCommercial 4.0 International license (CC BY-NC 4.0 DEED). To Cite Data: Hill, S. C. May 15 2005 Theta Aurora SWMF Simulation Data & Results [Data set], University of Michigan - Deep Blue Data. https://doi.org/10.7302/9fgf-9459