Jasper S. Halekas - University of Iowa

My long form CV.
Also see my Google Scholar Page.


This recent article describes MAVEN observations of "The Day the Solar Wind Disappeared at Mars".


This recent article describes Parker Solar Probe measurements of the energy budget of the solar wind and the relative influence of the Sun's electric field and plasma waves on the solar wind's acceleration.


This recent article describes Parker Solar Probe measurements of the radial evolution of the solar wind and the influence of the Sun's electric field on the wind's acceleration.


This paper describes measurements of a unique feature in the electron distributions only observable near the Sun, which allows us to determine the electric potential of the solar wind.


This paper describes the first measurements of electron heat flux in the innner heliosphere by Parker Solar Probe. We find that the electron heat flux is regulated, most likely by collisionless plasma instabilities.


This paper describes an innovative technique to obtain correlations between charged particle and electromagnetic field data at higher time resolutions than the intrinsic cadence of the charged particle measurements.


This paper describes our first results from the SWEAP SPAN-Electron sensors on Parker Solar Probe.


This paper investigated the structure of the ion composition boundary layer and the plasma instabilities that take place in this region. We identified two distinct classes of instability that occur on opposite flanks of the Martian magnetosphere.


This paper utilizes ARTEMIS measurements of plasma frequency oscillations to probe the tenuous lunar ionosphere present when the Moon traverses the Earth's magnetospheric tail.


This paper utilizes MAVEN observations to reveal the global structure of the Martian magnetosphere under different solar wind conditions, including the primary force terms in the momentum equation. This paper received an Editor's Highlight in Eos.


This paper describes unique new observations from MAVEN which show that the hydrogen exosphere of Mars varies by an order of magnitude over the Martian year, with a peak near southern summer solstice.


This paper describes the inflight performance and first results from the Solar Wind Ion Analyzer, the instrument I lead for the MAVEN mission. Some of the new results include a global overview of magnetospheric structure and variabiliy, and some of the first measurements of Alfven waves and foreshock dynamics at Mars.


This paper describes a new method for analyzing pickup ion observations, which allows us to constrain atmospheric composition by timing the delay in the response of pickup ions to the passage of magnetic field discontinuities. Our results suggest a surprisingly large contribution from heavy exospheric species.


This paper in GRL discusses MAVEN observations of bulk escape of plasma from Mars in the form of coherent "clouds" that are stripped away from Mars by the solar wind.


I was third author of and led the charged particle investigation described in one of our four initial Science papers from MAVEN, which presented the exciting results from our subsolar deep dip campaign, where we measured the structure and dynamics of a region of the upper atmosphere never previously visited.


I was heavily involved in one of our four initial Science papers from MAVEN, describing the impact of a significant space weather event on the magnetosphere of Mars.


Our MAVEN first results include a paper that I led describing the deposition of solar wind hydrogen in the Martian atmosphere. This hydrogen undergoes a charge exchange with the corona, penetrates the magnetosphere as an energetic neutral atom, and then undergoes electron stripping or electron attachment to convert to H+ or H- that we can observe with MAVEN.


Our MAVEN first results include a paper that I led describing the first observation of time-dispersed ion signatures at Mars. These appear to be created by pickup of heavy Martian ions in time variable electric fields.


A paper describing LADEE NMS ion-mode observations of newly born ions from the tenuous lunar exosphere. These new data show that the lunar exosphere contains an unexpected population of carbon-bearing particles, apparently originating from either solar wind or micrometeorite bombardment.


A paper from 2014 describing the latest ARTEMIS observations of small-scale collisionless shocks generated by solar wind reflection from lunar magnetic fields. This paper provides the strongest evidence to date that shocks actually do form at the Moon, and suggests that these may be some of the smallest collisionless shocks in the solar system, at least in terms of plasma scales.