Dr Adam J. Finley
@adamfinley.bsky.social
ESA Research Fellow at ESTEC in the Netherlands. Investigating the Sun's magnetic activity, solar wind connection science, and the spin-down of Sun-like stars. Previously a postdoc at CEA Paris-Saclay and PhD at Uni of Exeter.
Comparison at the time of Orbiter:
September 24, 2025 at 7:35 AM
Comparison at the time of Orbiter:
Beautiful double erruption in 304A observed by GOES/SUVI and Solar Orbiter over the east-limb (slightly later) in the low-latency data.
September 24, 2025 at 7:35 AM
Beautiful double erruption in 304A observed by GOES/SUVI and Solar Orbiter over the east-limb (slightly later) in the low-latency data.
The Alfvén radius is linked to the solar wind mass and magnetic flux. The wind magnetisation parameter (~ratio of mag/mass flux), is used to understand this dependence. Our results follow the trends from MHD wind simulations, but had an offset that is likely due to 3D effects and turbulence. (5/8)
September 10, 2025 at 10:43 AM
The Alfvén radius is linked to the solar wind mass and magnetic flux. The wind magnetisation parameter (~ratio of mag/mass flux), is used to understand this dependence. Our results follow the trends from MHD wind simulations, but had an offset that is likely due to 3D effects and turbulence. (5/8)
Towards maximum activity, the heliospheric current sheet became complex and the solar wind sources moved towards the active latitudes. So, for example, an encounter of PSP that spends more time in the solar wind near current sheets will have a smaller Alfvén radii on average. (7/8)
September 10, 2025 at 10:43 AM
Towards maximum activity, the heliospheric current sheet became complex and the solar wind sources moved towards the active latitudes. So, for example, an encounter of PSP that spends more time in the solar wind near current sheets will have a smaller Alfvén radii on average. (7/8)
A very dipolar magnetic field became inclined to the rotation axis. (6/8)
September 10, 2025 at 10:43 AM
A very dipolar magnetic field became inclined to the rotation axis. (6/8)
The heliospheric current sheet became warped by the emergence of active regions. (5/8)
September 10, 2025 at 10:43 AM
The heliospheric current sheet became warped by the emergence of active regions. (5/8)
The evolution of the coronal magnetic field during the solar cycle, strongly influenced the magnetic connectivity of PSP. Each encounter is different, which obscures our perception of the average Alfvén radius. Near minimum, the wind measured by PSP originated closer to the Sun's poles. (4/8)
September 10, 2025 at 10:43 AM
The evolution of the coronal magnetic field during the solar cycle, strongly influenced the magnetic connectivity of PSP. Each encounter is different, which obscures our perception of the average Alfvén radius. Near minimum, the wind measured by PSP originated closer to the Sun's poles. (4/8)
We mapped the wind back to its source using the Parker spiral and a potential field source surface model. The Alfvén surface was modulated by structure in the corona. Smaller near current sheets and pseudo-streamers, larger near the dipole axis and expanding magnetic field. (3/8)
September 10, 2025 at 10:43 AM
We mapped the wind back to its source using the Parker spiral and a potential field source surface model. The Alfvén surface was modulated by structure in the corona. Smaller near current sheets and pseudo-streamers, larger near the dipole axis and expanding magnetic field. (3/8)
Using hourly measurements from the SWEAP and FIELDS suites, we mapped PSP to the Alfvén surface with a Parker spiral. Each encounter had a distribution of radii. The longitudinal-average reduced the bias from individual wind streams, the average grew from 10-16 solar radii. (2/8)
September 10, 2025 at 10:43 AM
Using hourly measurements from the SWEAP and FIELDS suites, we mapped PSP to the Alfvén surface with a Parker spiral. Each encounter had a distribution of radii. The longitudinal-average reduced the bias from individual wind streams, the average grew from 10-16 solar radii. (2/8)
Side project day! NASA's Parker Solar Probe (PSP) has been exploring the near-Sun enviroment since the start of solar cycle 25. Now passing maximum activity, how has the shape and size of the Sun's Alfvén surface evolved since? arxiv.org/abs/2509.07088 (1/8)
September 10, 2025 at 10:43 AM
Side project day! NASA's Parker Solar Probe (PSP) has been exploring the near-Sun enviroment since the start of solar cycle 25. Now passing maximum activity, how has the shape and size of the Sun's Alfvén surface evolved since? arxiv.org/abs/2509.07088 (1/8)
New paper day! Metcalfe et al. review the evidence for weakened magnetic braking around the Sun's age by homogenizing the stellar parameters from previous studies that constrained the wind braking of stars with observed magnetic fields and x-ray fluxes (proxy for mass-loss): arxiv.org/pdf/2509.03717
September 5, 2025 at 10:09 AM
New paper day! Metcalfe et al. review the evidence for weakened magnetic braking around the Sun's age by homogenizing the stellar parameters from previous studies that constrained the wind braking of stars with observed magnetic fields and x-ray fluxes (proxy for mass-loss): arxiv.org/pdf/2509.03717
3D view of this plot:
September 2, 2025 at 11:43 AM
3D view of this plot:
Approaching perihelion (16th Sept.), the structure of the coronal magnetic field is similar to our prediction from July. The Sun's dipole field remains fully inclined with nested active regions influencing the heliospheric current sheet. Solar Orbiter will be mostly connnected to active latitudes.
September 2, 2025 at 11:43 AM
Approaching perihelion (16th Sept.), the structure of the coronal magnetic field is similar to our prediction from July. The Sun's dipole field remains fully inclined with nested active regions influencing the heliospheric current sheet. Solar Orbiter will be mostly connnected to active latitudes.
ESA Solar Orbiter is zooming towards the Sun (perihelion at 0.29au on the 16th Sept.), currently at 0.44au the spacecraft has a nice view of the south pole (combined image from EUI/FSI). Coronal holes, filaments, active regions, lots of things to investigate!
September 2, 2025 at 8:23 AM
ESA Solar Orbiter is zooming towards the Sun (perihelion at 0.29au on the 16th Sept.), currently at 0.44au the spacecraft has a nice view of the south pole (combined image from EUI/FSI). Coronal holes, filaments, active regions, lots of things to investigate!
ESA's Solar Orbiter @esa.int @science.esa.int has begun to sned data home again after it passed superior conjunction on the far-side of the Sun to Earth. With Solar Orbiter slightly below the solar equator and Earth slightly above, we get a nice 360 degree view of the solar surface. ☀️🔍👀
August 28, 2025 at 1:19 PM
ESA's Solar Orbiter @esa.int @science.esa.int has begun to sned data home again after it passed superior conjunction on the far-side of the Sun to Earth. With Solar Orbiter slightly below the solar equator and Earth slightly above, we get a nice 360 degree view of the solar surface. ☀️🔍👀
Looking at this swirling feature in the solar atmosphere, revealed that the viscous heating along the swirl boundary was connected with the breakdown of coherent oscillations in the swirl. The MSF/W method provides a new pathway to investigate wave activity in the solar atmosphere. (4/4)
August 28, 2025 at 11:39 AM
Looking at this swirling feature in the solar atmosphere, revealed that the viscous heating along the swirl boundary was connected with the breakdown of coherent oscillations in the swirl. The MSF/W method provides a new pathway to investigate wave activity in the solar atmosphere. (4/4)
Using this approach, horizontal slices of a realistic solar atmosphere were decomposed into their most significant frequencies. A biproduct of this method, the highest frequency bin highlights dissipation/shocks. This is especially clear at swirl boundaries. (3/4)
August 28, 2025 at 11:39 AM
Using this approach, horizontal slices of a realistic solar atmosphere were decomposed into their most significant frequencies. A biproduct of this method, the highest frequency bin highlights dissipation/shocks. This is especially clear at swirl boundaries. (3/4)
The MSF/W method uses discrete Fourier transforms to move variables into frequency/wavenumber space and identify the most significant contribution to that variable at a given time/place. An example of a signal decomposed into the most and 2nd most significant wavenumbers. (2/4)
August 28, 2025 at 11:39 AM
The MSF/W method uses discrete Fourier transforms to move variables into frequency/wavenumber space and identify the most significant contribution to that variable at a given time/place. An example of a signal decomposed into the most and 2nd most significant wavenumbers. (2/4)
New paper day! 🔥 George Cherry et al. develop the Most Significant Frequency/Wavenumber method for detecting wave activity in realistic magnetohydrodynamic simulations of the Sun's atmosphere. Published in A&A: www.aanda.org/articles/aa/... (1/4)
August 28, 2025 at 11:39 AM
New paper day! 🔥 George Cherry et al. develop the Most Significant Frequency/Wavenumber method for detecting wave activity in realistic magnetohydrodynamic simulations of the Sun's atmosphere. Published in A&A: www.aanda.org/articles/aa/... (1/4)
The magnetic energy in the quadrupole (l=2) and dipole (l=1) are now pretty comparable which may be why the solar corona is looking so dipolar. The octupole (l=3) is often in synch with the dipole and so the quadrupole is the main competitor when it comes to the large-scale structure.
August 4, 2025 at 2:12 PM
The magnetic energy in the quadrupole (l=2) and dipole (l=1) are now pretty comparable which may be why the solar corona is looking so dipolar. The octupole (l=3) is often in synch with the dipole and so the quadrupole is the main competitor when it comes to the large-scale structure.
Two crossings of the coronal hole at the negative dipole axis at 310 Carrington longitude. Closest approach in the south above the coronal hole at 180 degree (which may have closed by then). And a scan across the nested active regions at (-15,120) and (15,20), if they stay active until September..
July 28, 2025 at 8:56 AM
Two crossings of the coronal hole at the negative dipole axis at 310 Carrington longitude. Closest approach in the south above the coronal hole at 180 degree (which may have closed by then). And a scan across the nested active regions at (-15,120) and (15,20), if they stay active until September..
Here's the same process applied to the Autumn 2025 remote-sensing window:
July 28, 2025 at 8:56 AM
Here's the same process applied to the Autumn 2025 remote-sensing window:
Here's a comparison of the coronal magnetic field from solar minimum (Dec 2019) and now at solar maximum. The dipole component of the Sun's magnetic field is visibly inclined to the rotation axis.
July 27, 2025 at 2:52 PM
Here's a comparison of the coronal magnetic field from solar minimum (Dec 2019) and now at solar maximum. The dipole component of the Sun's magnetic field is visibly inclined to the rotation axis.
You can see the stability of the positive-negative sectors over the last five rotations, with two nested active regions (black contours) helping to restrict the heliospheric current sheet. GOES flares are shown with coloured markers. The dipole axis has just started to move away from the equator.
July 27, 2025 at 2:52 PM
You can see the stability of the positive-negative sectors over the last five rotations, with two nested active regions (black contours) helping to restrict the heliospheric current sheet. GOES flares are shown with coloured markers. The dipole axis has just started to move away from the equator.
At present, the Sun's large-scale magnetic field is well-described by an inclined dipole, with coronal holes near the positive and negative dipole axis. This has been the case for a year now. Solar Orbiter's path would cut across a large positive coronal hole twice around 60 degrees Car. longitude.
July 27, 2025 at 2:52 PM
At present, the Sun's large-scale magnetic field is well-described by an inclined dipole, with coronal holes near the positive and negative dipole axis. This has been the case for a year now. Solar Orbiter's path would cut across a large positive coronal hole twice around 60 degrees Car. longitude.