Philip Judge

AAS Nova Features a Recent Publication by Philip Judge

Six examples displaying corrugated surfaces at which the centers of UV lines are formed

Understanding the magnitude and occurrence of solar storms is key to predicting events that can be harmful to thousands of Earth-orbiting satellites and the welfare of astronauts.

The enduring mystery of the solar corona

Magnetic field lines
Thursday, September 16, 2021

The author reviews why, after almost 8 decades, we still have a coronal heating problem.

Why do we still have a coronal heating problem

The solar corona photographed by Miloslav Druckmüller from Brno University of Technology in the Czech Republic during the 2020 total eclipse over Argentina

After almost 8 decades, astronomers still debate the reasons why the Sun and sun-like stars must possess coronae. Philip Judge re-examines the problem and compares it to that of a detective trying to find the lead pipe or smoking gun at the scene of a murder.

Atomic structure calculations of Land ́e g factors of astrophysical interest with direct applications for solar coronal magnetometry

Non-relativistic Land ́e g factor
Thursday, May 6, 2021

We perform a detailed theoretical study of the atomic structure of ions with ns2npm ground configurations and focus on departures from LS coupling which directly affect the Land ́e g factors of magnetic dipole lines between levels of the ground terms.

Measuring the magnetic origins of solar flares, CMEs and Space Weather

A UV spectrum of α Cen A
Wednesday, April 21, 2021

We take a broad look at the problem of identifying the magnetic solar causes of space weather.

Magnetic structure of the solar chromosphere-corona transition regions

Graphic image of CLASP2 observations
Thursday, March 11, 2021

The bulk of the emission from the plasma called "transition region" plasma originates from structures energetically connected both to the chromosphere and corona.

On single-point inversions of magnetic dipole lines in the corona

Graphic image showing scattering geometry
Wednesday, March 3, 2021

Prompted by a recent paper by Dima and Schad, we re-consider the problem of inferring magnetic properties of the corona using polarimetric observations of magnetic dipole (M1) lines.

On the Cores of Resonance Lines Formed in the Sun's Chromosphere

Graphic image depicting a comparison of 1D and 3D calculations
Wednesday, July 1, 2020

We re-examine a 50+ year-old problem of deep central reversals predicted for strong solar spectral lines, in contrast to the smaller reversals seen in observations.

Neutral hydrogen, helium and solar and stellar coronae

Graphic image of Line Profiles of He I and He II Resonance Line
Wednesday, June 17, 2020

In the context of the solar atmosphere, we re-examine the role of of neutral and ionized species in dissipating the ordered energy of intermediate-mode MHD waves into heat.

Some thoughts on emission-line spectroscopy

Graphic image of intensity and polarization data surrounding the current sheet formed on Sept 10 2017
Tuesday, June 2, 2020

Philip Judge states that the interpretation of emission lines formed in large astrophysical plasmas such as the solar atmosphere faces many challenges. Relatively simple line-ratio estimates of physical parameters, while appealing, are heavily laden with assumptions.

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