• NASA Homepage
• Goddard Space Flight Center
• Sciences & Exploration Directorate

• Solar System Exploration Division
• Planetary Magnetospheres Laboratory
• MGS MAG/ER Science Team

Jared R. Espley earned his Ph.D. in Space Physics and Astronomy from Rice University in Houston, Texas in November 2005 under the direction of Dr. Paul Cloutier with a thesis entitled Low frequency plasma waves at Mars.
Available as PDF (21 MB).

Cesar Bertucci defended his Ph.D. Thesis, Study of the Interaction of the Solar Wind with Mars: Implications on the Atmospheric Escape Mechanisms, for Paul Sabatier University (Toulouse, France) degree requirements on the 2nd of December 2003 at the Centre d'Etude Spatiale des Rayonnements (CESR), Toulouse, France. He analyzed the solar wind interaction with Mars from Mars Global Surveyor (MGS) Magnetometer / Electron Spectrometer (MAG/ER) in order to deduce constraints on non-thermal atmospheric escape mechanisms related to this interaction. He analyzed high-amplitude highly coherent waves at the local proton cyclotron frequency never reported before. A theoretical study based on linear wave growth theory reveals that these waves are associated to the exospheric H+ pickup process. However, the characteristics of these waves and MHD Hall multi-fluid simulations suggest that nonlinear effects are involved in their origin. Theoretical studies are needed in order to establish constraints on exospheric model parameters and on the atmospheric loss rate from the properties of these waves. He also characterize the magnetic pileup boundary (MPB), a permanent plasma boundary located between the bow shock and the ionosphere. From a study of the magnetic field topology he demonstrate that the magnetic field line draping is strongly accelerated across the MPB. Equivalently, he demonstrate for the first time the existence of a MPB at Venus. Thus, the MPB is revealed to be a common boundary to all weakly magnetized, atmospheric bodies whose nature is deeply related to the multi-ion nature of their interaction.
Thesis available (in French).
French and English definitive versions of thesis in progress.

Yue Chen earned his Ph.D. degree in physics from the Physics and Astronomy Department of Rice University in Houston, Texas in January 2003 under the direction of Dr. Paul Cloutier with the dissertation entitled Effects of the charge exchange of solar wind with the Martian exosphere. He studied the dual effects of the charge exchange: on one hand, an enhancement of magnetic field caused by the charge exchange between solar wind and Martian exosphere leads to the observed steep magnetic field spatial gradient in the magnetic pile-up boundary, and a semi-empircal hydrodynamic model is developed and the results fit with the MGS MAG data; on the other hand, a Monte Carlo model predicts that the input of energetic netural hydrogen atoms from the charge exchanged solar wind protons will prominently alter the thermal structure of the Martian exosphere.
Available as PDF.

Dave Brain received a Ph.D. in Planetary Science from the University of Colorado at Boulder in July of 2002. His thesis, directed by Fran Bagenal, was titled The Influence of Crustal Magnetic Sources on the Topology of the Martian Magnetic Environment. The thesis examined MGS data to identify the different influences of the solar wind and crustal magnetic fields on magnetometer observations. The observations were compared to existing Martian magnetic field models, and a vacuum superposition model was used to make predictions about the Martian solar wind obstacle, field structure, and the location of open magentic field lines on Mars' dayside.
Available as PDF files.

Antonio Hernandez Barosio earned his PhD. from the Universidad Nacional Autonoma de Mexico (National University of Mexico) on the 11th of January 2002. His thesis, Origen y evolucion de la magnetizacion cortical del planeta Marte detectada por la mision "Mars Global Surveyor" (Origin and Evolution of the Mars crustal magnetization detected by the Mars Global Surveyor Mission), was prepared under the direction of Mario H. Acuña and J.F. Valdes. For Earth, the methods to interpret satellite maps of crustal magnetic sources usually start with a qualitative interpretation, which consists of visual comparisons of the maps of crustal magnetic sources with geological, tectonics, topographic, gravitational, heat flow, and crustal thickness maps. This comparisons provide us with important restrictions on the geological and geophysical processes that have operated on a particular region and permit us to associate magnetic sources to specific processes. This type of methodology is precisely the type that was used in this work, which is able to delimit and associate, in space and time, the origin and evolution of Mars crustal magnetic sources, recently detected by the Mars Global Surveyor (MGS) mission. Afterwards, taking as a base the results of the comparisons previously mentioned, it was proceeded to quantitatively model Mars crustal magnetic sources with the goal of planting and establishing the hypothesis that their origin is due to the crustal fracturization associated with the rising of the Tharsis Bulge and not to the expansion of ocean floor as suggested by other authors. Taking into consideration that the length of the magnetic sources is larger than their width, that the altitude of the spacecraft is smaller than the length of the sources, and that the region is geographically limited, it has been considered that a 2-D model is sufficiently exact to model said sources. In this model, it is assumed that the sources responsible for the magnetization detected can be modeled as a collection of small bodies of regular geometry and known magnetization, whose limits are based on the tectonic-structural characteristics mapped around the Tharsis Bulge. The expected magnetic field is modeled for different thickness of magnetized crust, which has been useful to establish the minimum thickness of magnetized crust that must exist to generate alternate magnetic sources (magnetic dipoles) and the maximum inclination and depth that the tectonic-structural systems must have to generate the observed dipole fields.

Didier Vignes, Étude du champ magnétique et de l'environnement ionisé de la planète Mars à l'aide des données de la sonde Mars Global Surveyor, Henri Rème and Christian Mazelle, CESR, January 2000.
Thesis available (in French).

Peter Walker, A global magnetic potential model for Venus' ionosphere, Paul Cloutier, Rice University, November 1999.
Abstract available.

Dana H. Crider earned her Ph.D. in Space Physics and Astronomy from Rice University in Houston, Texas in May 1999 under the direction of Dr. Paul Cloutier with a thesis entitled Evidence of Electron Impact Ionization in the Magnetic Pileup Boundary of Mars--Observations and Modeling Results. She simulated electron spectra from 10 eV - 20 keV in the Martian Magnetic Pileup Boundary and compared them to electron spectra data from the MGS MAG/ER experiment. She found that electron impact ionization of oxygen and hydrogen was able to reproduce the observed attenuation in electron fluxes across the Magnetic Pileup Boundary.
Available as PDF.

Contributors: Ever Guandique, Dana Crider, Dave Brain, Yue Chen, Cesar Bertucci, and Antonio Hernandez Barosio

• Privacy Policy and Important Notices.

• NASA Official: Ron Oliversen
• Email: Ronald.J.Oliversen@nasa.gov
• Curator: Patricia Lawton, ADNET Systems, Inc.
• Email: Patricia.J.Lawton@nasa.gov
• Last Modified: 18 January 2017