Research Interests | Project Involvement

Research Interests:

I conduct research into the basic properties of collisionless plasmas, by analyzing spacecraft observations of such plasmas in space. I am particularly interested in understanding the physics of magnetic reconnection and collisionless shocks. This research is also of practical importance, because ultimately it helps us to understand and predict Space Weather. Space weather research is our effort to understand how the conditions in space near the Earth are affected by the Sun.

Magnetic reconnection

I have mainly worked on observations of magnetic reconnection in the Earth's magnetotail, where it lies at the heart of the substorm process. Using Cluster, I have published evidence for multiple X-line reconnection, and investigated the Hall electric and magnetic fields that are the signatures of the reconnection ion diffusion region. More recently, I have studied the properties of turbulence generated by reconnection. I am currently investigating particle acceleration mechanisms, using data from Cluster and THEMIS.

I am also interested in how magnetic reconnection affects Mars' crustal magnetic field. In 2008 we published the first evidence of reconnection at Mars using data from Mars Global Surveyor (MGS). We are now studying its prevalence and statistical properties; this has implications for atmospheric loss at Mars, which will be studied by the MAVEN spacecraft which will launch to Mars in a few years time.

I have started a new project to study solar reconnection, using observations from the S/WAVES instrument on the STEREO spacecraft. In particular, Type III emission is generated by electron beams which may be produced by reconnection in the corona. I am particularly interested in Type III storms.

Collisionless shocks

The Earth's bow shock is one of the best places to make in-situ observations of collisionless shocks. During my doctoral work I used the novel capabilities of Cluster to study the different types of low frequency waves that are generated by backstreaming ion beams in the foreshock region. These waves play a crucial role in shock acceleration mechanisms. During my postdoctoral research at Goddard, I completed studies showing that the compressive properties of these waves are caused by wave refraction in the inhomogenous foreshock.

More recently, I have studied the structure of the quasi-perpendicular shock, and used THEMIS to study Hot Flow Anomalies, an interesting kinetic effect that occurs when a solar wind discontinuity hits the bow shock causing a global disruption.

 

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Projects I am Specifically Involved In:

I am associated with a number of science projects; some are operational, whereas others are in development or proposed.

 

In Flight:

Cluster: I have worked extensively on the multi-spacecraft Cluster mission. I am a Co-Investigator (ESA) on the Flux Gate Magnetometer. I was recently recognized as one of the 'top 10' contributing scientists.

THEMIS: I am also working on THEMIS (based here at Berkeley). I am a member of the Science Working Team, and one of the THEMIS tohban.

ARTEMIS: I am a Co-Investigator on the ARTEMIS mission - this is part of the THEMIS-ARTEMIS extended mission.

STEREO: I am a member of the STEREO S/WAVES Team.

 

In Development:

Magnetospheric Multi-Scale: I am a Co-Investigator on one of the Magnetospheric Multi-Scale (MMS) Interdisciplinary Science Teams (IDS) (PI - Tai Phan).

CINEMA: I am a member of the CINEMA team. CINEMA is an NSF funded cubesat project designed to study energetic neutral atoms from the radiation belts and magnetotail.

 

Proposed:

Cross Scale: I am a supporting scientist for the Cross-Scale mission, currently being studied by ESA.

Solar Orbiter: I am a Co-Investigator (ESA) on the Radio and Plasma Waves (RPW) experiment.