Upcoming presentation at AGU Fall Meeting 2016

SM44A-04:  The Soft X-ray Imager (SXI) on the SMILE Mission

Steven Sembay

Thursday, 15 December 2016  16:36 – 16:48

Moscone West – 2003

SMILE (Solar wind Magnetosphere Ionosphere Link Explorer) is a space mission dedicated to study the interaction of the solar wind with the Earth’s magnetic field. SMILE will investigate the dynamic response of the Earth’s magnetosphere to the impact of the solar wind in a unique manner, never attempted before: it will combine soft X-ray imaging of the Earth’s magnetic boundaries and magnetospheric cusps with simultaneous UV imaging of the Northern aurora, while simultaneously providing context measurements via an in situ plasma and magnetometer instrument package. SMILE is a joint European Space Agency (ESA) and Chinese Academy of Sciences (CAS) collaborative mission due for launch in 2021.

This talk will describe the Soft X-ray Imager (SXI) on SMILE. The SXI is designed for good detection sensitivity of the soft X-rays (0.2 – 2.0 keV) produced in the Earth’s exosphere by the solar wind charge exchange process. This process is the mechanism by which it is possible to globally image the Earth’s dayside magnetosheath, magnetopause boundary, bowshock and cusps. The wide field of view of the instrument (27° x 16°) is achieved by the use of a micropore optic (MPO) with a Lobster-eye focusing geometry. The detector consists of two large format CCDs (each 8.1 cm x 6.8 cm sensitive area) providing high quantum efficiency and medium energy resolution for soft X-rays. The instrument design will be presented along with simulation results indicating the instrument sensitivity and science return.

Upcoming presentation at AGU Fall Meeting 2016

SM44A-07:  Science Objectives for a Soft X-ray Mission

David Sibeck

Thursday, 15 December 2016  17:12 – 17:24

Moscone West – 2003

When high charge state solar wind ions exchange electrons with exospheric neutrals, soft X-rays are emitted. In conjunction with flight-proven wide field-of-view soft X-ray imagers employing lobster-eye optics, recent simulations demonstrate the feasibility of imaging magnetospheric density structures such as the bow shock, magnetopause, and cusps. This presentation examines the Heliospheric scientific objectives that such imagers can address. Principal amongst these is the nature of reconnection at the dayside magnetopause: steady or transient, widespread or localized, component or antiparallel as a function of solar wind conditions. However, amongst many other objectives, soft X-ray imagers can provide crucial information concerning the structure of the bow shock as a function of solar wind Mach number and IMF orientation, the presence or absence of a depletion layer, the occurrence of Kelvin-Helmholtz or pressure-pulse driven magnetopause boundary waves, and the effects of radial IMF orientations and the foreshock upon bow shock and magnetopause location.

Upcoming presentation at AGU Fall Meeting 2016

SM33B-2509:  Magnetopause Surface Reconstruction from Tangent Vector Observations

Michael Collier

Wednesday, 14 December 2016  13:40 – 18:00

Moscone South – Poster Hall

Entire fields of science, most notably in astrophysics, rely on line-of-sight observations. In planetary science and heliophysics, the techniques of soft X-ray and energetic neutral atom (ENA) imaging produce line-of-sight measurements. An important question is whether the geometry of the surface, for example the magnetopause, can be reconstructed using only line-of-sight observations from a single spacecraft. Under a broad range of conditions, the peak emission corresponds to the tangent to the boundary surface, such as the planetary surface or magnetopause (e.g., Collier et al., JGR: Planets, 119, 2014, doi:10.1002/2014JE004628 and Collier et al., JGR: Space Physics, 110, 2005, doi:10.1029/2004JA010626), the so-called “limb brightening” phenomenon. Thus, the tangent to the surface is frequently one quantity these techniques measure. Mathematically, the tangent vector plays a central role in differential geometry. We present an algorithm to reconstruct the magnetopause cross-sectional surface using these principles from line-of-sight soft X-ray observations (and, in principle, ENA observations, as well). Using soft X-ray simulations, we have examined the effectiveness of the algorithm.

Upcoming presentation at AGU Fall Meeting 2016

SM33B-2512:  The STORM and CuPID soft X-ray cameras on the DXL sounding rocket mission: Employment of slumped micropore optics to image solar wind charge exchange X-ray emission in the magnetosheath.

Nicholas Thomas 

Wednesday, 14 December 2016  13:40 – 18:00

Moscone South – Poster Hall

Upcoming presentation at AGU Fall Meeting 2016

SM44A-06:  Simulating the Magnetosheath in X-rays 

Kip D Kuntz

Thursday, 15 December 2016  17:00 – 17:12

Moscone West – 2003

Over the last decade, interest has focussed on imaging the magnetosheath using the soft X-ray emission due to solar wind charge exchange (SWCX) with the Earth’s exosphere. We have developed the capability to simulate observations of the SWCX from the magnetosheath in order to evaluate instrument designs, orbital parameters, and mission profiles. Our method begins with a magneto-hydrodynamic model of the magnetosheath (np, vp, and Tp) and a model of neutral distribution (nn). We scale the Q = ∫npnnvrel dl by the production factor Ϛ determined by Kuntz et al in order to determine the X-ray emissivity along the line of sight. This emissivity is further scaled to the band-pass of interest using the model spectra of Koutroumpa et al or Foster et al. We then apply an instrumental response and add suitable noise to simulate what an instrument would observe. These images can then be processed with standard imaging tools/techniques to determine how well the desired scientific quantities can be derived.

Here we concentrate on three successively interesting questions. 1) Under what solar wind conditions is the emission from the magnetosheath sufficiently strong to separate it from the soft X-ray background? 2) For what observing geometries can one measure the location of the magnetopause and the bowshock? 3) At what cadence can one observe the motion of the magnetopause at a useful spatial resolution? These latter two questions have required the development of an algorithm to locate the magnetopause and bowshock within the images, which we describe. We demonstrate the capability of several projected and proposed missions.