Titan Atmospheric Loss Along Magnetic Field Lines



Marc Dennis, Darci Snowden

Faculty Mentor(s)

Darci Snowden (Physics)


Titan is the largest moon orbiting Saturn that is comparable in size to planets present in our solar system. Titan is compelling because the makeup of Titan’s atmosphere has a likeness to Earth’s. The scientific community is interested in understanding the loss rates of Titan’s atmosphere. The problem I am solving involves Titan’s atmospheric loss via outflow along the magnetic field of Saturn. Photochemical reactions in Titan’s atmosphere produce ions and photoelectrons that are more energetic than electrons normally found in the charged upper portion of the atmosphere, commonly known as the ionosphere. Energetic electrons escape along the magnetic field lines and create a charge-separation, making it possible for these ions to be pulled from the atmosphere due to the electric field created. The goal is to estimate loss rates due to ion outflow along these field lines. I have analyzed magnetic field data and electron density data collected from the Cassini spacecraft. I will establish the framework for a one-dimensional model to simulate ion outflow along magnetic field lines due to the ambipolar electric field. Future projects may involve more analysis and the creation of a model for two or three dimensions.

Keywords: Titan, Atmosphere, Space


6 thoughts on “Titan Atmospheric Loss Along Magnetic Field Lines”

  1. Hey Marc, wicked stuff! Just out of curiosity, how many flybys were ignored because they had “bad” data? And, beyond that, for all of these terms that you’ve ignored for now like collisions and gravity, how much will that impact the end result? From what I understand, I’d assuming things like gravity and collisions would have a huge impact because both of those would work against the particles escaping/moving in Titan’s ionosphere and thus have a large impact on the model but I’d love to know more! Super sick stuff though, nice work!

    1. Hey, thanks Henry. I just went back and checked the flyby list and I only included roughly a third of the total flybys. It turns out that getting good data from a planet a billion kilometers away proves to be a little difficult. That second question is a good one because frankly, that’s a question I’d like to know the answer to myself! My guess would be that the overall shape of the data would stay the same, but the specific values would change. As to what those specific values may be… we’ll just have to wait and see as the model becomes more complex.

  2. Great job, Marc! I like how you started with a baseline model that will allow you to add additional factors like gravity and collisions one layer at a time so that you can gain insight into what each factor contributes. When you expand the model to 2 or 3 dimensions, do you expect the measured features vs. altitude to depend significantly on where you are with respect to Titan’s poles?

  3. Hi Marc, Thanks for sharing your presentation. Can you explain the radial and horizontal components of the magnetic field and why they have different strengths depending on the flyby? Does it have to do with the orientation of Cassini relative to Titan?

  4. Hi Marc! I liked your presentation, I thought you picked a fascinating subject to dig into and study. I especially liked your introduction!

    I have a question: have you considered looking into models of estimated gas loss rates on a planet from solar wind, and applying that research to this? I’ve heard there are a few papers out there which model how total atmospheric pressure, gravity, and weight of the gases determines the atmospheric loss rate from solar wind, and I think that has a lot of commonalities with your paper. Something like “Mars solar wind interaction: Formation of the Martian corona and atmospheric loss to space” might have techniques that you could talk to the authors about. Maybe you’ve already looked into it, but if not it could be a shortcut.

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