DOI: 10.5281/zenodo.17437447
title: Swarm-EMIC Research Project - EMIC database

description: This dataset comprises databases of electromagnetic ion cyclotron (EMIC) wave events detected by automated Pc1 wave finding algorithms developed by the VI3DLabs & University of Alberta team using Swarm 50 Hz magnetic field, 16 Hz electric field and 2 Hz Langmuir probe density datasets, as well as incorporating Canadian Space Agency CARISMA and NASA Van Allen Probes datasets. This dataset is published as a deliverable of the European Space Agency Swarm-EMIC project which aims to use Swarm datasets to investigate the impact of EMIC waves on energetic electron precipitation. A link to the project description can be accessed here: ttps://eo4society.esa.int/projects/swarm-emic/

The dataset is in CSV format (N x 29 matrix) with the column values defined below. 

tsBegin - EMIC event beginning (timestamp in datenum format)tsEnd - EMIC event ending (timestamp in datenum format)duration - EMIC event duration in secondsfCtr - event centre frequency in HzfBW - event bandwidth (full-width half maximum, or FWHM) in Hzellip - ellipticity (-1 for left-hand circular polarised, 0 for linear, +1 for right-hand circular polarised)minP2P - minimum peak-to-peak magnitude of the event (nT)medianP2P - median peak-to-peak magnitude of the event (nT)maxP2P - maximum peak-to-peak magnitude of the event (nT)BminCtr - the B-field minimum of the field line at the event centre (traced to the equator using IGRF)EMICband - EMIC band based on observed frequency and the traced estimated equatorial gyrofrequencies from BminCtr. Values are as follows: 0 = above H+ gyro, 1 = below H+ gyro, 2 = below He+ gyro, 3 = below O+ gyro, -1 = tracing failed/unknown bandMLTbegin - MLT at the beginning of the eventMLTctr - MLT at the centre of the eventMLTend - MLT at the end of the eventLmBegin - the McIlwain L-shell at the beginning of the eventLmCtr - Lm at centre of the eventLmEnd - Lm at end of the eventLstarBegin - L* at beginning of eventLstarCtr - L* at centre of the eventLstarEnd - L* at end of the eventgeoLatBegin - geographic latitude (in deg) at event beginninggeoLatEnd - geographic latitude (in deg) at event endgeoLonBegin - geographic longitude (in deg) at event beginninggeoLonEnd - geographic longitude (in deg) at event endcgmLatBegin - corrected geomagnetic (CGM) latitude (in deg) at beginning of eventcgmLatEnd - CGM latitude (in deg) at end of the event cgmLonBegin - CGM longitude (in deg) at beginning of the eventcgmLonEnd - CGM longitude (in deg) at end of the eventEMICconf - EMIC event confidence level

The EMIC event confidence level ('EMICconf') is defined on a 1-6 scale as follows: 

1 - compressional Pc1 energy bounded from above and below by area of reduced power2 - transverse Pc1 energy bounded from above and below by area of reduced power3 - both compressional AND transverse Pc1 energy bounded from above and below by area of reduced power4 - as 3 but the centre frequency, lower and upper bounds (determined separately from half-maximum, i.e. 3dB either side of the peak) are within 0.5 Hz of each other5 - Pc1 event of at least level 2 is also conjugate with CARISMA ICM (100 Hz) ground magnetometers. Swarm and CARISMA FWHMs must overlap6 - Pc1 event of at least level 2 is also conjugate with Van Allen Probe satellite observations using EMFISIS fluxgate magnetometer (64 Hz). Swarm and VAP FWHMs must overlap

This database will be expanded in subsequent releases with new data from the 3 Swarm spacecraft. Any changes to the processing algorithms and format will be reflected in the new version Description file. 

The ZIP file ('SwarmEMICscripts.zip') contains the Matlab and Python codes which were used to generate the database. The code utilises the IRBEM field tracing library: https://prbem.github.io/IRBEM/ as well as the aacgmv2 Python package (https://github.com/aburrell/aacgmv2). 

For any questions, please reach out to Dr Ivan Pakhotin (i.pakhotin@vi3dlabs.com) or Prof Ian R Mann (imann@ualberta.ca).