Colloquia and Events



Department of Physics and Astronomy

California State University, Los Angeles


Understanding the Heliosphere and Solar Wind:

Insights from Parker Solar Probe

Dr. Marco Velli



The solar magnetic field plays a dual role in the generation of the Heliosphere. On the one hand it creates the corona by storing and transmitting, via a Poynting flux crossing the photosphere and transition region, the energy provided by the dynamo and convective motions; on the other hand, it provides the confinement, or magnetic cage, through which the heated coronal plasma must break through - everywhere except solar polar regions around solar minimum - to produce the supersonic solar wind.   Solar wind streams are characterized by different plasma properties, from overall speed, to temperature and temperature anisotropies, composition, as well as different properties for the embedded turbulence. Parker Solar Probe was launched to carry out the first in situ exploration of the outer solar corona and inner heliosphere with three overarching objectives: a) trace the flow of energy that heats and accelerates the solar corona and solar wind; b) determine the structure and dynamics of the plasma and magnetic fields at the sources of the solar wind; c) explore mechanisms that accelerate and transport energetic particles. Direct measurements of the plasma in the closest atmosphere of our star have produced significant surprises including the observation of the predominance of Alfvénic turbulence in solar wind streams, the presence of folds in the magnetic field called switchbacks that come in patches, magnetic reconnection in the forming heliospheric current sheets, anti-correlation of measured electron temperature with solar wind speed, and small-scale energetic particle events. Here I will introduce the Parker mission, discuss new results, and provide an updated view of our current understanding of solar magnetic activity and its interplanetary effects.


Thursday, Nov 30, 2023

Login 2:55 pm; Talk 3:05 pm

Viewing available in BIOS 241


Fall 2023 Department of Physics and Astronomy Colloquium Schedule

(All talks presented via Zoom unless otherwise stated. This schedule will be updated throughout the semester.)

  • August 31: Meet & Greet with Faculty - in-person
  • September 7: Dr. Abhinav Deshpande, Caltech/IBM, "Advancing quantum computing through experimentally-motivated theory: the emergence of non-classicality"
  • September 14: Dr. Ishan Mishra, NASA-JPL, "Decoding the chemical and physical nature of airless planetary bodies: examples from studies of Europa and Pluto"
  • September 21: Dr. Giada Arney, NASA-Goddard, "Earth is more than one planet: Lessons from Earth history on biosignatures for the Habitable Worlds Observatory"
  • September 28: Dr. Minhyea Lee, University of Colorado Boulder, "Magnetism and Competing Interactions in Quantum Materials"
  • October 5: Dr. Amanda Brecht, NASA-Ames, "Using General Circulation Models to Understand Terrestrial Planetary Atmospheres"
  • October 12: Dr. Mike Chaffin, University of Colorado Boulder, "The Atmospheric Escape Diet: An easy way to slim your planet's waterline and make the ponds fly off!"
  • October 19: Dr. Harry Themann, CSULA, "Beyond Standard Model Physics, The Elusive Neutrino Finally Comes Through" - in-person
  • October 26: Dr. Giulia Palermo, UC Riverside, "Dynamics and mechanisms of CRISPR-Cas9 through the lens of computational methods"
  • November 2: Dr. Iryna Butsky, Caltech, "Cosmic Rays and the Circumgalactic Medium"
  • November 9: Dr. Arneil Reyes, Florida State University, "Untangling the exotic physics of charge order in kagome lattices"
  • November 16: Dr. Anna Rosen, San Diego State University, "A Massive Star is Born: How Stellar Wind Feedback Limits Accretion onto Massive Stars"
  • November 23: Thanksgiving, campus closed
  • November 30: Dr. Marco Velli, UCLA, "Understanding the Heliosphere and Solar Wind: Insights from Parker Solar Probe"
  • December 7: Last week - no colloquium