About Me

I'm a post-doctoral researcher in the Planetary Magnetospheres group at the Dublin Institute for Advanced Studies (DIAS). My research focuses on the study of Jupiter’s dynamic ultraviolet aurorae, the intense northern and southern lights surrounding the planet’s magnetic poles. These aurorae result directly from interactions between Jupiter’s ionosphere and vast magnetosphere which are communicated by powerful current systems, all of which must be studied together to better understand the aurorae. I primarily use observations from the Hubble Space Telescope (HST), with the addition of data from the Galileo and Juno missions to Jupiter and models of currents flowing through Jupiter's magnetic field, to better understand these aurorae specifically and the magnetic environment of Jupiter generally. Understanding Jupiter's aurorae gives us insight into Jupiter's ionosphere and magnetosphere-- the region of Jupiter's atmosphere dominated by charged particles, rather than neutral gas, and the region of space dominated by Jupiter's magnetic field, respectively. These insights allow us to better understand planetary magnetic fields throughout the solar system (and beyond!) and allow better planning of future missions to Jupiter and other planets. In the DIAS Planetary Magnetosphere group, I plan to extend my expertise to include contemporary Juno measurements of Jupiter’s plasma environment, auroral emissions outside the Jovian Main Emission and in wavelengths other than the ultraviolet, and deeper modeling of the Jovian magnetosphere.

Research Interests

Jupiter's Aurorae

Jupiter displays intense ultraviolet aurorae in defined, bright arcs about the northern and southern magnetic poles. Multiple forms of aurorae occur on the planet: footprint aurora associated with the Gallilean moons; the main oval aurora resulting from the internal dynamics of the Jovian magnetosphere; and the polar aurora resulting from the interplay between the solar wind and Jupiter's magnetic field. The main auroral oval-- the most consistent and, on average, brightest of these-- is my main research interest.

Jupiter's magnetosphere is, by far, the largest object in the solar system-- the magnetopause, or sunward side of the magnetosphere, is ~5 solar radii away from the planet, while the distance down the magnetotail can be as high as 5 AU, reaching the orbit of Saturn. The Jovian magnetosphere is dominated by the rotational dynamics of plasma generated by the volcanically active moon Io, which generates nearly 1 ton/s of plasma. The continual loading of the magnetosphere with plasma is responsible for powerful field-aligned current systems that flow along the planet's magnetic field lines into Jupiter's atmosphere. Where these currents reach a maximum, the energetic electrons carrying the current create Jupiter's ultraviolet main auroral oval.

Observations of Jupiter's main auroral oval, carried out both by space-based observatories like the Hubble Space Telescope and probes like Gallileo and Juno have poked holes in this simple picture. Does the solar wind really only interact with the polar aurora, or does it influence the main auroral oval too? Do auroral emission on the main oval always corotate with the magnetosphere?

The Dawn Storms

The key to discovering the role of the solar wind in the deep interior of Jupiter's mangetosphere lies in understanding the "dawn storms." Jupiter's auroral dawn storms are historically rare events which are bright enough to dominate the emissions of the entire main oval for their short, few-hour lifetimes. The most interesting thing about these storms is not their intensity, however, but their behavior: they form on the main oval, where the aurora is expected to corotate with planet, yet they appear to remain fixed in local time. This behavior is unexplained, and suggests that the dawn storms both originate in the deep interior of the magnetosphere and are influenced by the sun (or the solar wind). Reconciling these two characteristics should reveal something new and fundamental to Jupiter's magnetosphere as a whole.

The Hydrogen Bulge

Where the dawn storms are interesting because they do not corotate (but should), Jupiter's hydrogen bulge is interesting because it does corotate (but shouldn't). The hydrogen Lyman-alpha bulge, or just the hydrogen bulge, is not a physical change in Jupiter's shape, as the name might imply, but an unexplained increase in the equatorial H Ly-alpha emission near longitudes of 100 deg. The emission originates in Jupiter's upper atmosphere, where winds and other dynamics should dictate its motion; instead, the hydrogen bulge corotates with the planet. Corotation is not expected for an atmospheric phenomenon and indicates some connection to the magnetosphere, but the drivers must be different than in the auroral regions, as no increased H2 emission-- which dominates the aurorae-- has ever been measured near the bulge. Many processes have been put forth to explain these fast H atoms, but observations have not yet been able to distinguish between these.

CV

Contact

Email: mrutala (at) bu.edu

Center for Space Physics
Boston University
725 Commonwealth Ave.
Boston, MA 02215