Philip Judge

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.

Introducing a Book— The Sun: A Very Short Introduction

Photographic image of the book cover to "The Sun: A Very Short Introduction" by Phil Judge

Philip Judge is a senior researcher in physics at the High Altitude Observatory. Education and outreach has been a major focus and passion during his scientific career. He has influenced and encouraged many young scientists to pursue careers in solar physics.

Spectropolarimetric Insight into Plasma-Sheet Dynamics of a Solar Flare

Graphic of intensity and polarization data
Wednesday, February 12, 2020

We examine spectropolarimetric data from the CoMP instrument, acquired during the evolution of the September 10th 2017 X8.2 solar flare on the western solar limb. CoMP captured linearly polarized light from two emission lines of Fe XIII at 1074.7 and 1079.8 nm, from 1.03 to 1.5 solar radii.

Multiwavelength High-resolution Observations of Chromospheric Swirls in the Quiet Sun

Graphic image of chromospheric swirls
Wednesday, February 5, 2020

We report observations of small-scale swirls seen in the solar chromosphere. They are typically 2 Mm in diameter and last around 10 minutes.

Sun-Like Stars Shed Light on Solar Climate Forcing

Seasonally averaged data for the CaII“S-index” and for the average magnitudes of the Strömgrenbplusy filters
Tuesday, January 7, 2020

Recently published, precise stellar photometry of 72 Sun-like stars obtained at the Fairborn Observatory between 1993 and 2017 is used to set limits on the solar forcing of Earth’s atmosphere of ±4.5 W m−2 since 1750.

Solar eclipse observations from the ground and air from 0.31 to 5.5 microns

Plot showing Spectra of the limb photosphere during the 21st August 2017 eclipse
Friday, March 29, 2019

We present spectra and broad-band polarized light data from a suite of instruments deployed during the 21st August 2017 total solar eclipse. Our goals were to survey solar spectra at thermal infrared wavelengths during eclipse, and to test new technology for measuring polarized coronal light.

High cadence visible and infrared spectra of the Sun during eclipse

Graph of raw counts are plotted against wavelength in air for spectral lines
Friday, February 1, 2019

We study visible and infrared spectra, from 310 nm to 5 microns, obtained during the 21st August 2017 eclipse. The instruments were situated at Camp Wyoba (altitude 2402 m) on Casper Mountain, WY.

Spectroscopy and atomic physics

the solar spectrum
Friday, May 4, 2018

A short guide to spectroscopy is given, with emphasis upon the elementary physics needed to understand and begin modeling the radiation emerging from astrophysical plasmas using the Sun as a guide, without bias towards a particular region of the Sun's atmosphere.

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