The kickoff meeting of the WaLSA Team took place at the University of Oslo (Oslo, Norway), between 7-11 January 2019, as a "Rosseland International Team", supported by the Research Council of Norway (project no. 262622). The entirely interactive meeting was aimed at improving scientific knowledge and stumulating new research objectives under the "umbrella topics" listed below, in the field of MHD waves in the lower solar atmosphere. From the challenges raised during the meeting, several new (original) science projects were created.
Challenges in the theory and observations of wave excitation and dissipation mechanisms
Challenges in the spectropolarimetric characterisation of MHD wave modes
Challenges in the use of non-linear and non-stationary analysis techniques
Challenges in the simulations of wave propagation in realistic solar atmospheres
Challenges in the observations of waves along complex solar structures
Challenges related to the design of new instrumentation for wave observations
Solutions to challenges with upcoming DKIST & EST observations
The second meeting of the WaLSA Team was held at the Rosseland Centre for Solar Physics (RoCS), in Oslo, Norway, during 12-16 August 2019. The meeting was funded by the Research Council of Norway through its centre of excellence, RoCS (project number 262622). In addition to a few allocated “umbrella topics” (listed below), to address other key challenges of the topic, the meeting was mostly dedicated to in-depth discussions of the challenges reviewed in the two meetings, followed by exploring observational data, theory, and models/simulations linked to our ongoing research projects started during, or after, the first team meeting in Oslo.
Challenges in MHD wave modelling and simulation with LARExD, MANCHA, CO5BOLD, Bifrost, and MURaM codes
Challenges in the modelling and observations of MHD shocks
Open problems and identiﬁcation of research projects linked to MHD waves in sunspots and small magnetic elements
Identiﬁcation of research projects linked to wave studies with ALMA
The third meeting of the WaLSA Team, held at the Kavli Royal Society Centre, Chicheley Hall (Newport Pagnell, Buckinghamshire, UK), on 10-11 February 2020, focused on presenting results of the research projects identified during the previous meetings in Oslo, including those related to spectropolarimetry and radiative transfer in the optically thick atmosphere. Implications imposed on upcoming next-generation ground-based facilities such as DKIST and EST, alongside space and balloon-borne missions like Solar Orbiter and Sunrise, were also discussed. The meeting was supported by a generous grant from The Royal Society (award no. Hooke18b/SCTM) as a Theo Murphy international scientific meeting (meeting's website).
Waves in the Lower Solar Atmosphere: examining small-scale magnetic elements as a source of waves
HMI observations of MHD waves in the lower solar atmosphere
Multi-fluid effects on chromospheric waves
Wave coupling and heating of expanding flux tubes in the chromosphere
Acoustic-gravity wave propagation characteristics in 3D radiation hydrodynamic simulations of the solar atmosphere
Oscillations observed with ALMA
Properties of local oscillations in lower sunspot atmospheres
Comprehensive MHD simulations of the solar atmosphere from quiet to active Sun
The modelling and interpretation of magnetohydrodynamic wave modes in sunspots and pores
The polarization profiles of Ca ii 854.2 nm in a Quiet Sun simulation
Waves captured by spectropolarimetric IBIS obversations
Two-fluid shocks in an isothermal stratified atmosphere
Waves in the lower solar atmosphere: setting the scene for the next generation of solar telescopes
The forth meeting of the WaLSA Team was held at the International Space Science Institute (ISSI) in Bern, Switzerland, during 19–22 April 2022. Due to some travel restrictions (because of the COVID situation), the meeting was organised in a hybrid format, with both in-person and online attendees. The main focus of the meeting was on presenting the ongoing research projects of the team and discussion on further challenges (linked to wave studies in the solar atmosphere), hence, brain-storming some new ideas (meeting's website).
Global p-modes in the solar atmosphere at high resolution
Acoustic-gravity wave spectra from numerical simulations
Discussion on potential wave studies with Solar Orbiter
Magnetoconvection simulations with PI effects ar 20, 10, and 5 km resolution
Comparison of wave propagation characteristics in 3D RHD simulations — an update
Phase dispersion relations in observations and simulations
The response of spectral observations to chromospheric oscillations
Sunspots are fund spots (modelling wave modes in sunspots)
Vortices and waves / Torsional motions and waves in the solar atmosphere
The Alfvénic nature of swirls in the solar atmosphere
Alfvénic waves in super-penumbral fibrils
Small-scale MHD waves in the solar chromosphere with ALMA
WaLSAtools: WaLSA wave analysis tools
Classification of Ca ii 854.2 nm profiles employing Self-Organised Maps (SOM)
Spatially coherent wave patterns in solar magnetic structures
The energy carrying potential of high-frequency waves in solar chromospheric spicules
The fifth meeting of the WaLSA Team was held at the International Space Science Institute (ISSI) in Bern, Switzerland, between 9–13 January 2023, thanks to ISSI for a prestigious grant (to organise two one-week meetings during 2022-2023; ISSI Team 502).
The format of this meeting was more 'work' orientated, with in-depth discussions around specific projects. As such, a group discussion on the first morning resulted in developing 7-8 high priority projects that the team could work on during the week. These included wave studies from high-resolution observations with DKIST, Solar Orbiter, SST, DST, and SDO as well as from state-of-the-art numerical simulations with the CO5BOLD, Mancha, and Bifrost codes. Due to the limited capacity of in-person attendees at ISSI-Bern, a few members of the team joined the discussion remotely.
The next science meeting of the WaLSA team will be held in Oslo, Norway (in January 2024), being hosted and funded by the Rosseland Centre for Solar Physics, University of Oslo.