Relevance of Murchison Widefield Array Interplanetary Scintillation Observations to Heliospheric Transient Catalogues

TL;DR

This study compares MWA interplanetary scintillation observations with heliospheric transient catalogues, revealing MWA's unique ability to detect transients, especially out-of-ecliptic, that other methods may miss, over a 7-month solar minimum period.

Contribution

The paper demonstrates that MWA IPS observations can identify heliospheric transients beyond the reach of traditional catalogues, enhancing detection and characterization of CMEs and SIRs.

Findings

68% of catalogued events have MWA IPS data

58% of IPS enhancements match catalogued events

MWA detects out-of-ecliptic transients missed by other methods

Abstract

We have conducted a comprehensive comparison of interplanetary scintillation (IPS) observations taken by the Murchison Widefield Array (MWA) with several heliospheric transient event catalogues, over a time period of 7 months during solar minimum. From this analysis we have found that of the 84% of catalogued events that have MWA IPS data available, 68% of them appear in MWA observations. Of the enhancements first identified in IPS observations, only 58% have a potential match with a catalogued event. The majority of enhancements that were identified in the IPS observations were situated greater than 10$^\circ$ from the ecliptic plane. Two such features were selected for detailed analysis, connecting their solar origins to their propagation through the heliosphere. The first of these features was created by a coronal mass ejection (CME), captured over two successive MWA observations and recorded in several catalogues. The second feature has the potential of being a stream interaction region (SIR) travelling out of the ecliptic plane. This particular SIR was not recorded in any catalogue. Thus the MWA shows promise in detecting heliospheric transients that other commonly-used techniques may overlook. These results show the strength of the MWA in having unbridled access to the heliosphere, able to make remote observations of events far out of the ecliptic as it is not restrained to the orbits of spacecraft. We demonstrate how the inclusion of MWA IPS data can potentially boost the number of CME and SIR events that are characterised.