Searcharxiv⌕ Search

arXiv · physics/0401131

In-situ acoustic-based analysis system for physical and chemical properties of the lower Martian atmosphere

Abstract

The Environmental Acoustic Reconnaissance and Sounding experiment (EARS), is composed of two parts: the Environmental Acoustic Reconnaissance (EAR) instrument and the Environmental Acoustic Sounding Experiment (EASE). They are distinct, but have the common objective of characterizing the acoustic environment of Mars. The principal goal of the EAR instrument is "listening" to Mars. This could be a most significant experiment if one thinks of everyday life experience where hearing is possibly the most important sense after sight. Not only will this contribute to opening up this important area of planetary exploration, which has been essentially ignored up until now, but will also bring the general public closer in contact with our most proximate planet. EASE is directed at characterizing acoustic propagation parameters, specifically sound velocity and absorption, and will provide information regarding important physical and chemical parameters of the lower Martian atmosphere; in particular, water vapor content, specific heat capacity, heat conductivity and shear viscosity, which will provide specific constraints in determining its composition. This would enable one to gain a deeper understanding of Mars and its analogues on Earth. Furthermore, the knowledge of the physical and chemical parameters of the Martian atmosphere, which influence its circulation, will improve the comprehension of its climate now and in the past, so as to gain insight on the possibility of the past presence of life on Mars. These aspect are considered strategic in the contest of its exploration, as is clearly indicated in NASA's four main objectives on "Long Term Mars Exploration Program" (http://marsweb.jpl.nasa.gov/mer/science).

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

F. A. Farrelly, A. Petri, L. Pitolli, G. Pontuale. 2004-01-26. In-situ acoustic-based analysis system for physical and chemical properties of the lower Martian atmosphere. https://doi.org/10.1016/j.pss.2003.08.021

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

A living catalog of stream interaction regions in the Parker Solar Probe era

Stream interaction regions (SIRs) and corotating interaction regions (CIRs) are important phenomena in heliospheric physics. These large-scale structures vary temporally and spatially, both in latitude and with radial distance. The additions of Parker Solar Probe (PSP) and Solar Orbiter have allowed for investigations into the radial evolution of these structures over a wide range of heliocentric distances for the first time since the Helios era. To better enable investigations of SIRs and CIRs within the inner heliosphere, we have developed a living catalog of SIR and CIR observations by Parker Solar Probe with corresponding observations by STEREO-A as well as ACE and Wind at 1 au. The methodology used for the identification of events and the generation of this catalog, the initial catalog of PSP observations spanning orbits one through five along with corresponding 1 au observations, and information on accessing the living catalog for future studies is described. This list of SIR and CIR events from PSP and corresponding observations from other heliophysics missions will enable case studies utilizing unique orbital arrangements, as well as aid in future statistical studies to further understand the properties and evolution of these structures.

physics.space-ph↗

Delayed maximum energy solar energetic particle events: Statistical analysis from Solar Orbiter

Investigations of solar energetic particles (SEPs) have long utilized the dispersive nature of onset times, as in, the earlier arrival of higher-energy particles compared to lower-energy particles, to infer information such as the path length to the acceleration site at the time of initial particle release. However, recent observations by Solar Orbiter and Parker Solar Probe have begun to characterize SEP events with an apparent delay in arrival times of the higher energy portion of the particle distribution, above a critical energy separating the delayed particles from that of the typical velocity dispersion signature at lower energies. Features of these delayed maximum energy (DME) SEP events, sometimes referred to as "inverse velocity dispersion" events, could provide new insight into the impacts of magnetic connectivity to locations along an expanding coronal mass ejection-driven (CME-driven) shock wave, variations of acceleration along the shock surface, and transport effects in the inner heliosphere. This study focuses on the occurrence rate and characteristics of DME events observed by Solar Orbiter relative to their footpoint locations with respect to the initial flare site. These DME events show a bias in occurrence rate towards events when the observer's footpoints were westward of the associated flare location. Additionally, estimated locations at which the highest-energy particles of DME events are released into the flux tube suggest continued release of increasingly higher-energy particles from the CME-driven shock into the connected flux tube well into the inner heliosphere. This indicates that DME events could be attributed to inner heliospheric effects and are not actually coronal in origin. This finding is consistent with previous observations and interpretations of SEP events connected westward of the associated flare.

physics.space-ph↗

Structure of energy flux densities in Earth's magnetotail reconnection regions: Bridging simulation and observation

Magnetic reconnection is important in both space and laboratory contexts because it changes the topology of magnetic fields and converts magnetic energy into particle energies. Establishing where this energy conversion occurs is critical for understanding how reconnection partitions energy. Using a novel machine learning approach based on simulations that explicitly identifies the separatrix regions for the first time, the partition of energy flux densities within the magnetic reconnection site is evaluated through statistical study of magnetotail reconnection events observed in situ. The separatrices are found to have the largest electron energy flux densities, roughly twice those in the exhaust, and Poynting flux densities about four times those in the inflows, whereas typical ion enthalpy flux densities are largest in the exhaust. The separatrices are therefore sites of intense electron and electromagnetic energy transport, although their small thickness means that the exhaust may still carry most of the total energy flux.

physics.space-ph↗