Extensive Study of a Coronal Mass Ejection with UV and WL coronagraphs: the need for multi-wavelength observations

Abstract

Coronal Mass Ejections (CMEs) often show different features in different band-passes. By combining data in white-light (WL) and ultraviolet (UV) bands, we have applied different techniques to derive plasma temperatures, electron density, internal radial speed, etc, within a fast CME. They serve as extensive tests of the diagnostic capabilities, developed for the observations provided by future multi-channel coronagraphs (such as Solar Orbiter/Metis, ASO-S/LST, PROBA-3/ASPIICS). The involved data include WL images acquired by SOHO/LASCO coronagraphs, and intensities measured by SOHO/UVCS at 2.45 R${}_{\odot }$ in the UV (H I Ly$\alpha$ and O VI 1032 {AA} lines) and WL channels. Data from the UVCS WL channel have been employed for the first time to measure the CME position angle with polarization-ratio technique. Plasma electron and effective temperatures of the CME core and void are estimated by combining UV and WL data. Due to the CME expansion and the possible existence of prominence segments, the transit of the CME core results in decreases of the electron temperature down to $10^5$ K. The front is observed as a significant dimming in the Ly$\alpha$ intensity, associated with a line broadening due to plasma heating and flows along the line-of-sight. The 2D distribution of plasma speeds within the CME body is reconstructed from LASCO images and employed to constrain the Doppler dimming of Ly$\alpha$ line, and simulate future CME observations by Metis and LST.

arXiv commentAccepted by ApJ, 22 pages, 12 figures

References in corpus (19)

• The Two Sources of Solar Energetic Particles
• Observation of An Evolving Magnetic Flux Rope Prior To and During A Solar Eruption
• Direct Detection of a CME-Associated Shock in LASCO White Light Images
• Far UV Spectra of Fast Coronal Mass Ejections Associated with X-class Flares
• On the Relationship Between a Hot-channel-like Solar Magnetic Flux Rope and its embedded Prominence
• Morphological evolution of a 3D CME cloud reconstructed from three viewpoints
• Homologous Jet-Driven Coronal Mass Ejections From Solar Active Region 12192
• The height evolution of the `true' CME mass derived from STEREO COR1 and COR2 observations
• First Empirical Determination of the Fe 10+ and Fe 13+ Freeze-in Distances in the Solar Corona
• A Solar Coronal Jet Event Triggers A Coronal Mass Ejection
• CME Induced Thermodynamic Changes in the Corona as Inferred from Fe XI and Fe XIV Emission Observations during the 2017 August 21 Total Solar Eclipse
• Determination of Coronal Mass Ejection physical parameters from combination of polarized visible light and UV Lyman-$\alpha$ observations
• Measure the Propagation of a halo CME and Its Driven Shock with the Observations from a Single Perspective at Earth
• Hot prominence detected in the core of a Coronal Mass Ejection: III. Plasma filling factor from UVCS Lyman-$\alpha$ and Lyman-$\beta$ observations
• First Determination of 2D Speed Distribution within the Bodies of Coronal Mass Ejections with Cross-Correlation Analysis
• 3D stereoscopic analysis of a Coronal Mass Ejection and comparison with UV spectroscopic data
• Properties of a Small-scale Short-duration Solar Eruption with a Driven Shock
• Uncertainties in polarimetric 3D reconstructions of coronal mass ejections
• Hydrogen Non-Equilibrium Ionisation Effects in Coronal Mass Ejections

Cited by in corpus (3)

• An Insight into the Coupling of CME Kinematics in Inner and Outer Corona and the Imprint of Source Regions
• Combining White Light and UV Lyman-alpha Coronagraphic Images to determine the Solar Wind Speed: the Quick Inversion Method
• Parameter effects on the total intensity of H I Lyα line for a modelled coronal mass ejection and its driven shock