Dr Julia Stawarz

I work in the area space plasma physics, which focuses on the study of the gasses of ionized particles, called plasma, in our solar system that are accessible to us with detailed measurements from spacecraft. These plasmas include the Sun, the solar wind & its interaction with the local interstellar plasma, and the magnetospheres of the Earth and other planets. Many of the plasma phenomena that we observe in our solar system are also relevant to the wide array of other plasmas found throughout the Universe – as such, the exceptionally detailed measurements that we can obtain from in situ spacecraft are an invaluable tool for studying fundamental plasma physics. My team uses these spacecraft measurements alongside numerical simulations and theory to better understand the fundamental physics of plasmas and how these processes impact the interaction between the Sun and Earth.

One of my primary areas of research is the study of plasma turbulence. Turbulence refers to the complex, seemingly chaotic motions that are a hallmark of many natural fluid and plasma systems – from the ocean and atmosphere on Earth to exotic astrophysical environments. In space and astrophysical environments, turbulence plays a crucial role heating and accelerating particles, mixing different plasma populations, and shaping the structure that we see in the Universe. However, understanding the nonlinear dynamics of turbulence remains one of the most enigmatic problems in classical physics and its interface with the unique features of astrophysical systems, such as the presence of magnetic fields and absence of collisions between individual particles, creates a rich landscape of important unsolved scientific questions.

Some of the key areas my team and I currently work on are:

Interplay between turbulence and magnetic reconnection – High-resolution measurements from NASA’s Magnetospheric Multiscale mission are providing us with an unprecedented new capability to systematically identify and analyse magnetic reconnection events associated with the complex magnetic configurations created by the turbulent dynamics. These measurements have revealed how turbulence can lead to novel forms of magnetic reconnection, such as the recently identified electron-only magnetic reconnection. Alongside my PhD student Paulina Quijia Pilapaña, we are exploring how machine learning can be used to aid in the identification of such turbulence-driven reconnection events, as well as how magnetic reconnection shapes the nonlinear interactions of the turbulence and contributes to turbulent dissipation.  

Turbulent electric fields and collisionless energy dissipation – The absence of collisions between particles in many space plasmas means dissipation does not occur via viscosity/resistivity as we are familiar with from terrestrial fluids. Instead, dissipation must occur through a wide range of collisionless kinetic processes (such as magnetic reconnection above) mediated by the interaction between the charged particles and their collective electromagnetic fields – this can have crucial impacts on how energetic particles can become and how energy is distributed between particles, but remains poorly understood. Alongside my PhD student Harry C. Lewis (based at Imperial College London), we are examining the nature of turbulent electric fields to reveal how they mediate the energy exchange with the particles and relate to specific plasma phenomena.

Modelling the impact of plasma turbulence – The wide-range of length and times scales in large space and astrophysical systems makes them notoriously challenging to accurately model with numerical simulations – particularly if the small-scale turbulent dynamics need to be resolved. With my postdoc Dr Jeffersson Agudelo Rueda, we are exploring how to better model the impact of collisionless turbulence on the large-scale evolution of astrophysical systems via simplified models motivated by a combination of fully kinetic simulations and cutting-edge spacecraft measurements.

Turbulence in the expanding solar wind – Turbulence is thought to play a key role in the acceleration and heating of the solar wind as it expands out into interplanetary space. Using unique alignments between two spacecraft – NASA’s Parker Solar Probe and ESA’s Solar Orbiter – that are traveling closer to the Sun than ever before, I am examining how the turbulence evolves as it expands into interplanetary space and how it provides the energy that accelerates and heats the solar wind.

Looking beyond our solar system – I am currently involved in leading the writing of a book on Electron Kinetic Physics: The Next Frontier in Space and Astrophysical Plasmas with a team of researchers from across solar, space, planetary, and astro- physics organised through an International Space Science Institute (ISSI) workshop that aims to explore the role that collisionless electron physics plays across the wide range of plasma environments in our Universe and specifically contrast the similarities and differences between the environments that we can directly measure in our solar system with those in more remote astrophysical locals.

Developing the next generation of space plasma missions – I am particularly interested in developing new space plasma missions that will answer the next-generation of questions in the field. I am involved in the Science Study Team for ESA’s proposed M7 candidate mission Plasma Observatory, which is planned to use a constellation of 7 spacecraft to make key measurements of cross-scale coupling, particle energisation, and energy transport across a wide range of different regions in near-Earth space that have astrophysical relevance. I have also been involved in leading the development of a preliminary mission concept called DREAM that would use a novel sensor design to provide new measurements of electron field-particle correlations, providing crucial new insights into electron energisation and the thermodynamics of collisionless plasmas.

• Please visit the Pure Research Information Portal for further information
• In situ observations of large-amplitude Alfvén waves heating and accelerating the solar wind, Rivera, Y., Badman, S., Stevens, M., Verniero, J., Stawarz, J., Shi, C., Raines, J., Paulson, K., Owen, C., Niembro, T., Louarn, P., Livi, S., Lepri, S., Kasper, J., Horbury, T., Halekas, J., Dewey, R., De Marco, R., Bale, S. 30 Aug 2024, In: Science
• Magnetospheric Multiscale measurements of turbulent electric fields in earth's magnetosheath: How do plasma conditions influence the balance of terms in generalized Ohm's law?, Lewis, H., Stawarz, J., Franci, L., Matteini, L., Klein, K., Salem, C., Burch, J., Ergun, R., Giles, B., Russell, C., Lindqvist, P. 7 Aug 2023, In: Physics of Plasmas
• Preface to Special Topic: Plasma Physics from the Magnetospheric Multiscale Mission, Stawarz, J., Genestreti, K. Apr 2023, In: Physics of Plasmas
• Turbulence-driven magnetic reconnection and the magnetic correlation length: Observations from Magnetospheric Multiscale in Earth's magnetosheath, Stawarz, J., Eastwood, J., Phan, T., Gingell, I., Pyakurel, P., Shay, M., Robertson, S., Russell, C., Contel, O. 4 Jan 2022, In: Physics of Plasmas
• Comparative Analysis of the Various Generalized Ohm's Law Terms in Magnetosheath Turbulence as Observed by Magnetospheric Multiscale, Stawarz, J., Matteini, L., Parashar, T., Franci, L., Eastwood, J., Gonzalez, C., Gingell, I., Burch, J., Ergun, R., Ahmadi, N., Giles, B., Gershman, D., Contel, O., Lindqvist, P., Russell, C., Strangeway, R., Torbert, R. Jan 2021, In: Journal of Geophysical Research: Space Physics

• Please visit the Pure Research Information Portal for further information
• Editorial work: Physics of Plasmas (Journal) 2022

Paulina Quijia Pilapaña Identifying magnetic reconnection to assess its role in the turbulent dynamics of the Earth’s Magnetosheath plasma Start Date: 01/10/2023

• Astrophysics PhD May 07 2016
• Astrophysics MSc December 20 2013
• Physics BSc May 21 2011
• Fellow Royal Astronomical Society 2020
• Member European Geosciences Union 2019
• Member American Geophysical Union (AGU) 2010

• Please visit the Pure Research Information Portal for further information
• Google Scholar
• CV