Search Publications
Establishing the Context for Reconnection Diffusion Region Encounters and Strategies for the Capture and Transmission of Diffusion Region Burst Data by MMS
Eastwood, J. P.; Fujimoto, M.; Phan, T. D. +4 more
This paper describes the efforts of our Inter-Disciplinary Scientist (IDS) team to (a) establish the large-scale context for reconnection diffusion region encounters by MMS at the magnetopause and in the magnetotail, including the distinction between X-line and O-line encounters, that would help the identification of diffusion regions in spacecraf…
Mission Oriented Support and Theory (MOST) for MMS—the Goddard Space Flight Center/University of California Los Angeles Interdisciplinary Science Program
Hwang, Kyoung-Joo; Goldstein, Melvyn L.; El-Alaoui, Mostafa +8 more
The MOST IDS team was tasked with focusing on two general areas: The first was to participate with the Fast Plasma Investigation (FPI) team in the development of virtual detectors that model the instrument responses of the MMS FPI sensors. The virtual instruments can be "flown through" both simulation data (from magnetohydrodynamic, hybrid, and ki…
Substorm Current Wedge Revisited
Lester, M.; Nakamura, R.; McPherron, R. L. +7 more
Almost 40 years ago the concept of the substorm current wedge was developed to explain the magnetic signatures observed on the ground and in geosynchronous orbit during substorm expansion. In the ensuing decades new observations, including radar and low-altitude spacecraft, MHD simulations, and theoretical considerations have tremendously advanced…
Origin and Evolution of the Cometary Reservoirs
Dones, Luke; Brasser, Ramon; Kaib, Nathan +1 more
Comets have three known reservoirs: the roughly spherical Oort Cloud (for long-period comets), the flattened Kuiper Belt (for ecliptic comets), and, surprisingly, the asteroid belt (for main-belt comets). Comets in the Oort Cloud were thought to have formed in the region of the giant planets and then placed in quasi-stable orbits at distances of t…
Cometary Isotopic Measurements
Jehin, Emmanuël; Engrand, Cécile; Sheridan, Simon +12 more
Isotopic ratios in comets provide keys for the understanding of the origin of cometary material, and the physical and chemical conditions in the early Solar Nebula. We review here measurements acquired on the D/H, 14N/15N, 16O/18O, 12C/13C, and 32S/34S ratios i…
The Composition of Comets
Mumma, Michael J.; Cochran, Anita L.; Schleicher, David G. +10 more
This paper is the result of the International Cometary Workshop, held in Toulouse, France in April 2014, where the participants came together to assess our knowledge of comets prior to the ESA Rosetta Mission. In this paper, we look at the composition of the gas and dust from the comae of comets. With the gas, we cover the various taxonomic studie…
Review on Current Sheets in CME Development: Theories and Observations
Reeves, Katharine K.; Lin, Jun; Raymond, John C. +5 more
We introduce how the catastrophe model for solar eruptions predicted the formation and development of the long current sheet (CS) and how the observations were used to recognize the CS at the place where the CS is presumably located. Then, we discuss the direct measurement of the CS region thickness by studying the brightness distribution of the C…
Current Sheets in the Earth Magnetotail: Plasma and Magnetic Field Structure with Cluster Project Observations
Nakamura, Rumi; Zelenyi, Lev; Artemyev, Anton +2 more
Thin current sheets having kinetic scales are an important plasma structure, where the magnetic energy dissipation and charged particle acceleration are the most effective. It is believed that such current sheets are self-consistently formed by the specific nonadiabatic dynamics of charged particles and play a critical role in many space plasma an…
Supernova Remnants Interacting with Molecular Clouds: X-Ray and Gamma-Ray Signatures
Slane, Patrick; Castro, Daniel; Ellison, Donald C. +2 more
The giant molecular clouds (MCs) found in the Milky Way and similar galaxies play a crucial role in the evolution of these systems. The supernova explosions that mark the death of massive stars in these regions often lead to interactions between the supernova remnants (SNRs) and the clouds. These interactions have a profound effect on our understa…
Large-Eddy Simulations of Magnetohydrodynamic Turbulence in Heliophysics and Astrophysics
Brandenburg, Axel; Velli, Marco; Toomre, Juri +9 more
We live in an age in which high-performance computing is transforming the way we do science. Previously intractable problems are now becoming accessible by means of increasingly realistic numerical simulations. One of the most enduring and most challenging of these problems is turbulence. Yet, despite these advances, the extreme parameter regimes …