ABSTRACT:

In December 1995, the Galileo probe entered the atmosphere of Jupiter with entry velocity of 48 km/s, or more than 110,000 miles per hour, making it the most ambitious atmospheric entry ever attempted. At such high speeds the atmospheric gas surrounding the probe turns into plasma (collection of charged particles) and its temperature increases to more than 100,000 ˚F. To survive, Galileo was equipped with a heat shield, which burned in a controlled way, thus carrying the heat away from the rest of the spacecraft. Although the mission was a success, the heat shield occupied about half the mass of the probe, leaving little space for scientific instruments. Development of lighter and more advanced heat shields requires testing material
destruction in extreme plasma heating conditions, which are very difficult to achieve on Earth… … Unless you consider using a tokamak!

A tokamak is a donut-shaped machine which can generate plasma as hot as the Sun and as dense as the plasma surrounding the Galileo probe while entering Jupiter. This talk reports on experiments where destruction of carbon-based materials (typically used for spacecraft heat shields) was studied at high heating environments available in the DIII-D tokamak. In this presentation, we will discuss how the laboratory experiment compares to the space conditions, how the experiments were designed and executed, and how to determine the amount of hear shield material lost for different heats. The results from our study are used to validate and improve theoretical models developed in the space community for missions like Galileo.

Work supported by US DOE under DE-SC0021338, DE-SC0021620, and DE-FC02- 04ER54698.

BIO:

Dr. Eva Kostadinova works as an assistant professor at Auburn University’s Department of Physics. She obtained her undergraduate degree at Furman University and her Ph.D. at Baylor University. Although the focus of her work is studying fundamental principles of plasma physics, she likes to call her research “interfacial” as it always lies at the intersection of multiple disciplines, including applied mathematics, space physics, aerospace engineering, and fusion science. Specific current projects include studying how charged dust particles self-organize into structures in plasma environments on Earth and on the International Space Station, as well as how fast electrons interact with twisted and curved magnetic fields. Most recently, she started
investigating how materials behave when exposed to a very hot plasma, which helps us develop heat shields for spacecrafts and understand how meteorites burn as they enter the Earth. Currently, Eva is the chair of Coalition of Plasma Science (CPS) – a non-profit organization, which aims to foster awareness of the full range of research, development, and industry involving plasma science.

If you can’t get enough of plasmas, check out the CPS website: https://www.plasmacoalition.org/