On the Formation Mechanism of Martian Dayside Ionospheric Plasma Depletion Events

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F24%3A10484601" target="_blank" >RIV/00216208:11320/24:10484601 - isvavai.cz</a>

Result on the web

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=aG3M8gFloD" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=aG3M8gFloD</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1029/2023JE008227" target="_blank" >10.1029/2023JE008227</a>

Result language

angličtina

Original language name

On the Formation Mechanism of Martian Dayside Ionospheric Plasma Depletion Events

Original language description

Plasma Depletion Events (PDEs) are characterized by abrupt, localized reductions in ionospheric plasma density at least by an order of magnitude decrease. These events are observed over a limited range of altitudes, typically spanning a few tens of kilometers. We use Mars Atmosphere and Volatile Evolution spacecraft data to investigate the properties and possible formation mechanism of daytime PDEs, typically observed at altitudes above 250 km. We show, using two example events and statistical analysis, that the depletion events are associated with electrostatic fluctuations and increased electron temperatures. The events are further accompanied by enhanced fluxes of suprathermal electrons and light energetic ions. These are indicative of local plasma heating, possibly mediated by the electrostatic fluctuations. The heated plasma may eventually escape from the depletion region through the ambipolar diffusion. The Martian ionosphere, consisting of ions and electrons, is embedded in the planet&apos;s thin atmosphere. Density variations in the ionosphere, occurring on both large and small scales, can significantly impact the atmospheric loss process on Mars. One particular type of these ionospheric anomalies involves sudden reductions in ion density, often by tenfold or more. Although we have a basic understanding of these depletion events, their detailed characteristics and origins are not yet fully understood. We use data from various instruments onboard the Mars Atmosphere and Volatile Evolution spacecraft to investigate these phenomena, particularly on the dayside. We find that these depletion events are accompanied by increased electron temperatures and enhanced electric field fluctuations, while the magnetic field remains virtually unchanged. These observations suggest localized plasma heating within the depleted region. Furthermore, the fluxes of energetic light ions (mostly protons) and electrons are increased during the events. This increase in energetic particles could potentially serve as the energy source driving the heating process. We propose that the depletion events form when the heated ionospheric plasma escapes from the heated region. Large scale plasma density depletions in the Martian dayside ionosphere are linked with electrostatic fluctuations Increased electron temperatures, enhanced suprathermal electron fluxes, and energetic light ions are observed within the depleted regions Local plasma heating possibly drives electron escape, forming an ambipolar field and causing plasma depletions through ambipolar diffusion

Czech name

—

Czech description

—

Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10305 - Fluids and plasma physics (including surface physics)

Project

<a href="/en/project/LUAUS23152" target="_blank" >LUAUS23152: Electrodynamics of magnetospheres and ionospheres of the Earth, Jupiter and Mars</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>S - Specificky vyzkum na vysokych skolach<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2024

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Journal of Geophysical Research. Planets

ISSN

2169-9097

e-ISSN

2169-9100

Volume of the periodical

129

Issue of the periodical within the volume

6

Country of publishing house

US - UNITED STATES

Number of pages

15

Pages from-to

e2023JE008227

UT code for WoS article

001234744000001

EID of the result in the Scopus database

2-s2.0-85195140493