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BEGIN:VEVENT
DTSTAMP:20260524T145521Z
UID:https://www.mps.mpg.de/events/43216/7840847
DTSTART:20251002T090000Z
DTEND:20251002T100000Z
CLASS:PUBLIC
CREATED:20250928T130609Z
DESCRIPTION:Energetic events such as solar flares and coronal mass ejection
 s (CMEs)\, which can lead to solar storms\, are driven by the coronal magn
 etic field (CMF)\, whose structure and evolution remain not fully understo
 od. When Earth-directed\, these storms can trigger auroras - as observed i
 n Portugal in 2024 - but also pose serious risks to radio communications\,
  GPS systems\, power grids\, and satellite infrastructure.Under certain co
 nditions\, Extreme Ultraviolet (EUV) observations reveal useful informatio
 n about the 3D geometry of some magnetic field lines\, as the emitting pla
 sma is "frozen into" the magnetic field\, though they do not provide measu
 rements of the magnetic field. Unlike the solar surface - the photosphere 
 - where the magnetic field can be measured via spectropolarimetry\, this i
 s generally not achievable in the typically force-free corona\, due to the
  faintness and thermal broadening of spectral lines. As a result\, extrapo
 lation methods are used to infer the coronal magnetic field from routine p
 hotospheric measurements.The most widely used model\, the Potential Field 
 Source Surface (PFSS)\, is fast and computationally efficient\, but it cal
 culates a current-free\, minimal-energy coronal field using the low measur
 ement uncertainty photospheric radial magnetic field component. This limit
 s its accuracy in active regions\, where magnetic free energy - critical f
 or flares and CMEs - is stored. More advanced\, state-of-the-art Non-linea
 r Force-Free Field (NLFFF) models allow for electric currents and\, theref
 ore\, free energy\, leading to greater accuracy\, but they are computation
 ally intensive and highly sensitive to data quality.We developed a signifi
 cantly faster Python code built upon a functional optimization framework p
 reviously proposed and implemented by our team. In this new version\, we i
 ntroduce a three-term functional that simultaneously minimizes: (1) the an
 gle between the magnetic field and the tangents to observed EUV loops\, (2
 ) the divergence of the magnetic field\, and (3) the Lorentz force. Includ
 ing the Lorentz-force term enables our method to control the degree of for
 ce-freeness\, an essential physical property typically accessible only to 
 the more computationally demanding NLFFF models.By minimizing the proposed
  functional\, we derive the perturbations that are iteratively applied to 
 the original PFSS solution. The resulting magnetic field represents a trad
 e-off between alignment with EUV loops\, solenoidality (divergence-freenes
 s)\, and force-freeness\, yielding a more physically realistic configurati
 on.This approach retains the computational efficiency of PFSS while signif
 icantly improving the physical consistency of the solution. Validation aga
 inst EUV observations confirms the method's ability to produce magnetic fi
 eld solutions that are more accurate and observationally constrained\, pro
 viding a new\, efficient\, and reliable tool for coronal magnetic field st
 udies.\nSpeaker: Carlos António
LAST-MODIFIED:20250928T132207Z
LOCATION:https://uio.zoom.us/j/63138938090
ORGANIZER;CN=Valeriia Liakh:mailto:
SUMMARY:ESPOS: ESPOS: Advancing Solar Magnetic Field Modeling (Carlos Antó
 nio)
URL;VALUE=URI:https://www.mps.mpg.de/events/43216/7840847
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