An international team of scientists, using data collected by NASA’s Parker Solar Probe probe, has managed to create the first continuous two-dimensional map of the magnetic edge of Sol. Este landmark in heliophysics offers an unprecedented view of the so-called surface of Alfvén, the critical boundary where solar material escapes the star’s magnetic influence and becomes the solar wind that courses through the entire planetary system.
Research reveals that this boundary is not a smooth, uniform sphere, but rather a complex, irregular and constantly changing surface. Observations confirm that its shape and altitude vary drastically according to the 11-year cycle of solar activity, a key factor in understanding how energy is released by Sol.
This detailed mapping represents a significant advance for solar science, as it provides concrete data that validates and improves theoretical models about the solar atmosphere. Understanding the dynamics of the surface of Alfvén is crucial to unraveling ancient mysteries such as the anomalous heating of the solar corona and the acceleration of the solar wind.
Parker Solar Probe’s journey in the solar corona
Launched in 2018, the Parker Solar Probe mission was designed with the audacious goal of “touching Sol”, getting closer to our star than any other human artifact. Equipada with a state-of-the-art heat shield, the probe performs elliptical orbits that cause it to repeatedly dive into the outer atmosphere of Sol, the corona. It is during these passages, known as perihelia, that the spacecraft collects invaluable data about an extreme and previously unexplored environment.
The probe is equipped with a set of sophisticated instruments, with emphasis on SWEAP (Solar Wind Electrons Alphas and Protons), which directly measures particles in the solar wind. Unlike remote observatories that analyze the light emitted by the Sol, the Parker performs measurements in situ, that is, at the location itself. Essa’s ability allowed her to physically cross the surface of Alfvén on several occasions, providing essential validation for the data used in constructing the new map and confirming the exact location of this invisible boundary.
How the surface map of Alfvén was created
Creating the unprecedented map was a complex effort that combined different data sources. The researchers didn’t just rely on direct measurements of Parker Solar Probe. Eles integrated this information with remote observations from other strategic space missions, creating a more complete and robust portrait of the solar boundary.
Data from the Solar Orbiter probe, a collaboration between ESA and NASA that observes Sol from an intermediate distance, and from spacecraft positioned at Ponto of Lagrange L1, which continuously monitor the solar wind approaching Terra, were crucial. Utilizando a scaling technique, scientists projected measurements taken at great distances back to the vicinity of Sol.
The key point of the study was the use of real crossings of Parker as a “fundamental truth”. Quando the probe physically crossed the border, the data collected served to calibrate and confirm the accuracy of the map generated from remote projections. The notable coincidence between estimates and direct measurements gave high reliability to the method used.
The dynamics of the solar boundary over time
One of the most striking discoveries revealed by the map is the extremely dynamic nature of the surface of Alfvén, which transforms drastically in sync with the solar cycle. Over six years of observations, which covered the transition from minimum to maximum of solar cycle 25, scientists recorded that the average surface height increased by approximately 30%. Isso means that as Sol’s activity intensifies, with more sunspots and flares, its magnetic influence extends further into space, pushing the boundary outward. The shape of the surface also evolves: during periods of solar calm, it tends to be more rounded and smooth. Contudo, during solar maximum, it acquires a much more irregular and spiky structure, with bulges and valleys that reflect the complexity of the underlying magnetic field. Essas changes directly affect how and from where the solar wind is released, influencing its properties such as speed and density when it finally reaches Terra and the other planets.
What the irregular shape of the magnetic edge reveals
The map confirms that the surface of Alfvén is far from a perfect sphere, presenting a complex topography, described by scientists as “prickly” or “wrinkled”. Essa’s irregular structure is a direct reflection of the complex web of magnetic fields emanating from the visible surface of Sol.
These bulges and protrusions are not mere topographical details; they function as channels or preferential regions through which solar plasma can escape more easily into interplanetary space, giving rise to solar wind currents with distinct characteristics.
Interestingly, during its first few orbits, the Parker probe frequently “skimmed” the tops of these bulges before managing to consistently dive below the main layer of Alfvén’s surface. Somente with the intensification of solar activity, the boundary expanded enough for the probe to spend more time in the sub-Alfvénic environment.
The complexity of this boundary is directly linked to fundamental physical processes occurring in the corona, such as magnetic reconnection and plasma turbulence. Compreender its shape helps scientists better understand the origin of phenomena such as “switchbacks”, zigzag-shaped folds in the magnetic field of the solar wind.
Unlocking the secrets of coronal heating
Research on the surface of Alfvén has direct implications for one of the biggest enigmas in astrophysics: the problem of coronal heating. The solar corona reaches temperatures of millions of degrees Celsius, making it hundreds of times hotter than the visible surface beneath it, a counterintuitive phenomenon that defies the laws of conventional thermodynamics.
The energy that heats the corona is believed to be transported from the interior of the Sol by magnetic waves, known as Alfvén waves. The surface of Alfvén is the region where these waves and the plasma separate, defining the limit of energy transfer. Mapear this precision boundary allows scientists to test theories about how this energy is deposited in the corona and subsequently used to accelerate the solar wind.
The technology behind accurate measurements
The success of this unprecedented mapping cannot be attributed to a single mission, but rather to a synergistic collaboration between different space observatories. The combination of perspectives offered a three-dimensional and temporally rich view of the heliosphere. Enquanto to
Improving Space Storm Forecasting
In addition to its value for fundamental science, this research has direct practical applications in the field of space weather. Modelos More accurate information about the origin and propagation of the solar wind is essential to improve the ability to predict the arrival of solar storms and coronal mass ejections at Terra.
More accurate and far-ahead forecasting is vital to protecting critical infrastructure, both on the ground and in space. Tempestades Severe geomagnetic waves can damage communications and GPS satellites, overload electrical grids and pose a health risk to astronauts in orbit, making this advancement an important step towards global technological security.