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Catherine Cuddy

Publications and source records attributed to Catherine Cuddy.

2 recordsLinked to original sources

Multiple shocks generated by the 2024 May 14 coronal mass ejection

This study characterises a series of type~II radio bursts associated with a CME that occurred on 14 May, focusing on the coronal conditions during the event and identifying the likely location of the shocks where the radio bursts are generated. The CME was tracked using a combination of white light and extreme ultraviolet observations of the solar corona taken by three instruments: GOES-SUVI, two coronagraphs of the SOHO-LASCO, together with ground-based radio observations between 10-240~MHz from I-LOFAR. The radial distances of the radio sources were examined using a series of density models, with both PFSS and MHD models used to examine the coronal plasma conditions. Four type~II bursts were identified in the I$-$LOFAR radio dynamic spectrum over $\sim$15~minutes, exhibiting features such as band splitting, herringbones, and fragmentation. The shocks were found to have speeds ranging between $\sim$443$-$2075~km s$^{-1}$, with drift rates of $\sim-$361 to -78~kHz~s$^{-1}$. The shocks were found to have a $M_A \approx$ 3.21$-$3.57. indicating that they were super-Alfv\'enic. The first type~II burst was triggered $\sim$18~minutes after the CME launch, with each burst appearing to have been generated at a different height in the corona. Analysis of the derived kinematics and modelling results suggests that the type~II bursts were likely produced at the shoulders of the CME near the flanks, where open magnetic field lines and relatively low Alfv\'en speeds facilitated shock formation. This multi-instrument study shows that multiple type II bursts from a single CME originated at different coronal heights, with modelling indicating their generation near the CME flanks, where low Alfv\'en speeds and open magnetic field lines facilitated shock formation.

astro-ph.SR

Helical flows along coronal loops following the launch of a coronal mass ejection

Solar flares and coronal mass ejections (CMEs) are manifestations of energy release in the solar atmosphere, which can be accompanied by dynamic mass motions and waves in the surrounding atmosphere. Here, we present observations of plasma moving in a helical trajectory along a set of coronal loops formed following the eruption of a CME on 2024 May 14. This helical motion was observed in extreme ultraviolet (EUV) images from the Solar Dynamic Observatory (SDO), which provides new insights into plasma properties in a set of post-eruption coronal loops. We utilize images from the SDO Atmospheric Imaging Assembly (AIA) instrument to track the helical motion of plasma and to characterize its speed, acceleration, and physical properties. Additionally, we explore the evolution of the plasma density and temperature along the helical structure using the differential emission measure technique. The helical structure was visible in AIA for approximately 22 minutes, having a diameter of 22 Mm, and a total trajectory of nearly 184 Mm. Analysis of the AIA observations reveals that the plasma flow along this helical coronal loop exhibits speeds of 77-384 km s$^{-1}$ and temperatures ranging from 3.46 to 10.2 MK. Additionally, the densities were estimated to be between 4.3.106 and 1.55.107 cm-3, with an estimated magnetic field strength of 0.05-0.3 G. Following the launch of a CME, we find clear evidence for impulsive heating and expansion of plasma that travels a helical trajectory along a set of post-eruption loops. These observations provide an insight into impulsive plasma flows along coronal loops and indeed the topology of coronal loops.

astro-ph.SR