Geospace Missions for Space Weather and the Next Scientific Challenges James Spann, United States, NASA February 11, 2014

Beautiful motivation

Next Major Science Challenges Geospace Missions Observation Requirements Space-Based Ground-Based Future science missions Next Major Science Challenges Flare prediction – solar surface and subsurface dynamics Geoeffectiveness of Space Storms – interplanetary magnetic field Ionospheric variability – ubiquitous impact Discipline Challenge Operation tools and workforce

Observation Requirements

Space Weather Observing Systems for Geospace Mission Observations DSP Energetic particles GPS DMSP Energetic particles, imaging, density C/NOFS Ionospheric variability COSMIC GOES Magnetic fields, energetic particles POES & MetOp Iridium/AMPERE Magnetic fields THEMIS* Plasmas, fields Van Allen Probes* Radiation belt composition and energetic particles AIM* noctiluscent clouds TIMED* ITM parameters ISS Plasma/particle sensors, aeronomy E-POP* ion outflow SWARM* magnetometry Cluster* magnetospheric plasma, particle, field parameters Reimi* Auroral structures Akebono* Auroral physics GOLD** Thermospheric density & temperature variability ICON** MMS** Plasmas, particles, fields e-POP Payload on the CASSIOPE Satellite Artist's rendition of the e-POP payload on CASSIOPE The Institute for Space Imaging Science at the University of Calgary is leading the development of the Enhanced Polar Outflow Probe (e-POP), a scientific payload for CASSIOPE, the first, made-in-Canada multi-purpose small satellite mission from the Canadian Space Agency. The e-POP payload is in an elliptical polar orbit aboard CASSIOPE, circling the globe at altitudes between 325 and 1500 km. Launched on September 29, 2013, e-POP's eight scientific instruments are collecting new data on space storms and associated plasma outflows in the upper atmosphere and their potentially devastating impacts on radio communications, GPS navigation, and other space-based technologies. Space storms (also called solar storms because these disturbances originate from the sun) generate large electrical currents in the upper atmosphere's polar regions. The solar storms also produce the aurora borealis and aurora australis that are often referred to as the northern and southern lights, respectively. The CASSIOPE mission marks a new generation of smaller, cost-effective satellites. CASSIOPE has both a scientific and a commercial objective: it will provide scientists with unprecedented details about potentially dangerous space weather as well as demonstrate a new digital communications 'courier' service from MDA Corporation. The e-POP project is a key project within the Canadian Space Agency's space science program and involves contributions from 11 Canadian universities and research organizations. * science missions ** science missions in development

Ground-Based Ionospheric Sensors

INTERMAGNET Sites

Top rated future science missions in the US highlight Geospace space weather relevant missions The first new STP science target is to understand the outer heliosphere and its interaction with the interstellar medium, as illustrated by the reference mission Interstellar Mapping and Acceleration Probe (IMAP). Implementing IMAP as the first of the STP investigations will ensure coordination with NASA Voyager missions. The mission implementation also requires measurements of the critical solar wind inputs to the terrestrial system. The second STP science target is to provide a comprehensive understanding of the variability in space weather driven by lower-atmosphere weather on Earth. This target is illustrated by the reference mission Dynamical Neutral Atmosphere-Ionosphere Coupling (DYNAMIC).

Top rated future science missions in the US highlight Geospace space weather relevant missions The third STP science target is to determine how the magnetosphere-ionosphere-thermosphere system is coupled and how it responds to solar and magnetospheric forcing. This target is illustrated by the reference mission Magnetosphere Energetics, Dynamics, and Ionospheric Coupling Investigation (MEDICI). The survey committee describes the next science target best addressed by the LWS program (is) a mission to understand how Earth’s atmosphere absorbs solar wind energy, illustrated by the Geospace Dynamics Constellation (GDC).

IMAP A notional spacecraft and instrument implementation for IMAP is based largely on ACE and IBEX. IMAP is a Sun-pointed spinner, with spin axis readjustment every few days to provide all-sky maps every 6 months. Mission goals are achieved with a 2-year baseline, including transit to L1, with possible extension to longer operation (which would be particularly beneficial for long-term L1 monitoring). Observations from many spacecraft () contribute dramatically to understanding solar energetic particle events, the importance of suprathermal ions for efficient further energization, the sources and evolution of solar wind, solar-wind and energetic-particle inputs into geospace, and evolution of the solar-heliospheric magnetic field. These observables are controlled by a myriad of complex and poorly understood physical effects acting on distinct particle populations. IMAP combines highly sensitive PUI (pick-up ions) and suprathermal-ion sensors to provide the critical species, spectral coverage, and temporal resolution to address these physical processes. As an L1 monitor, IMAP also would fill a critical hole in Sun-Earth system observations by measuring the solar wind

New discoveries at the interface of the the heliosphere and the local intergallactic space give us some insight on very deep space weather. IMAP would explore that interface further and provide a robust platform for a L1 monitor of space weather.

DYNAMIC By resolving the fundamental question of meteorological influences from below, DYNAMIC will firmly connect the ionosphere-thermosphere (IT) system to Earth’s lower atmosphere, capturing a critical, missing component of scientific understanding of geospace and providing a critical new capability () at an important boundary in near-Earth space. In establishing the relative importance of thermal expansion, upwelling, and advection in defining total mass density changes, DYNAMIC will also provide information fundamental to understanding the global IT response to forcing from above. This investigation of the contribution of the lower atmosphere to the mean structure and dynamics of the IT system reflects a scientific appreciation of the importance of these drivers gained since the 2003 solar and space physics decadal survey.

DYNAMIC targets the effects of lower atmospheric processes on conditions in space, characterizing how the energy and momentum carried into this region by atmospheric waves and tides interact and compete with solar and magnetospheric drivers. Full spatial and temporal resolution of the wave inputs is accomplished by using two identical, high-inclination, space-based platforms in similar orbits, offset by 6 hours of local time

MEDICI MEDICI will both benefit from and enhance the science return from almost any geospace mission that flies contemporaneously, such as upstream solar wind monitors, geostationary satellites, and low-Earth-orbit missions. In particular, by providing global context and quantitative estimates for magnetospheric- ionospheric plasma and energy exchange, MEDICI has significant value for missions investigating ionospheric conditions, outflow of ionospheric plasma into the magnetosphere, energy input from the magnetosphere into the ionosphere, and aurora ionosphere-thermosphere coupling in general. Thus it will add value to a host of possible ionospheric strategic missions, Explorers, and rocket and balloon campaigns. Further, with continuous imaging and in situ observations from two separate platforms, it would provide indispensable validating observations of system-level interactions and processes that feed geospace predictive models. The likely long duration of the notional MEDICI mission will allow it to provide a transformative framework into which additional future science missions can naturally fit.

MEDICI targets complex, coupled, and interconnected multiscale behavior of the magnetosphere-ionosphere-thermosphere system by providing high-resolution, global, continuous three-dimensional images of the ring current(orange), plasmasphere (green), aurora, and ionospheric-thermospheric dynamics and flows, as well as multipoint in situ measurements.

Geospace Dynamic Constellation GDC will make measurements critical to understanding how the IT system regulates the response of geospace to external forcing. The constellation of satellites will provide a complete picture of the dynamic exchange of energy and momentum that occurs between ionized and neutral gases at high latitudes, providing the HSO a critical capability for measuring the response and electrodynamic feedback of Earth’s IT system to drivers originating in the solar wind and magnetosphere. GDC will also determine the global response of the IT system to magnetic activity and storms and expose how changes in the system at different locations are related. Finally, it will determine the influence of forcing from below on the IT system, by measuring the global variability of thermospheric waves and tides on a day-to-day basis with the spatial resolution that only a constellation of satellites can provide.

Features of the 6-spacecraft GDC mission concept

Are these Missions Real? The recommended highest priority science has significant space weather relevance in Geospace The science focus is real

Challenges Next Major Science Challenges Discipline Challenge Flare prediction – solar surface and subsurface dynamics Geoeffectiveness of Space Storms – interplanetary magnetic field Ionospheric variability – ubiquitous impact Discipline Challenge Operation tools and workforce development

Scientific Challenge: Geoeffectiveness Significant progress has been made predicting arrival time of space storms How geoeffective will a storm be? Sometimes yes, sometimes no Orientation of magnetic field and velocity are the first order determinants We have magnetic field orientation and magnitude at L1 with in situ monitors Goal: measure the orientation of the magnetic field as it evolves on its way to Earth

A concept to measure the inner solar system magnetic field Zodiacal light is scattered sunlight off interplanetary dust grains Dust grains rotate when illuminated, and become charged when exposed to UV and charged particles A rotating charged grain will align itself with mag field Alignment of a cloud of dust grains will produce polarized scattered light when illuminated Using polarimetry measurements and knowledge of dust grain optical extinction coefficient, the mag field direction can be inferred Measuring the interstellar magnetic field remotely as it traverses interplanetary space will provide significant advancement in our ability to predict the impact of space weather on Earth and at other magnetized bodies. Zodiacal light is a faint glow that appears close to the Sun in ecliptic is composed of scattered light and thermal emission from interplanetary dust grains. Composition? Silicates, olivine, peculiar shapes Dust grains respond to directional incident light by rotating about a preferential axis determined by the size, shape and surface properties of the grain. (Abbas et al. ApJ 614, 781, 2004) – radiative torque Dust grains are electrically charged when exposed to UV light (positive) and plasmas (negative). The residual charge on the grain depends on the surface work function of the grain, the light intensity and plasma density - reference A rotating charged object will align itself along the magnetic field direction – two primary mechanisms, not well established which is the dominant The alignment of a cloud of dust grains will produce polarized light – this is seen in interstellar space. In fact interstellar dust was discovered in the 1940’s by analysis of contaminant polarized light in astrophysical observations – reference Using polarimetry measurements with the knowledge of the optical extinction coefficient of the dust grains, and the number density of dust grains, the magnetic field direction can be inferred.

Scientific Challenge: Ionospheric Variability Ionospheric variability is arguably the most ubiquitous of all space weather effects on society Understanding the nature of the variability is very difficult Remote observations of the variability is elusive, but possible on large and small scales To make progress, in situ, ground-based, and large scale observations are needed

Daytime TEC : LISN Network – P.I. C. Valladares Day to day variability can be outstanding and currently defies prediction Noon Sector, December 24, 25, 26, 2011 Daytime TEC : LISN Network – P.I. C. Valladares Outstanding day-to-day variability in equatorial ionosphere while! New techniques show us behavior of the ionosphere that is completely unexpected. From Thomas Immel’s presentation at AMS Space Weather Conference 2.4-2014

Discipline Challenge: Develop a community of space weather operators Space science - scientists Space weather - meteorologists Develop an effective process to create decision making tools for space weather Governments Industries Meteorology paradigm Users/developers/scientists work very closely in an iterative fashion