Space Weather User Needs Related to Solar Observations Eamonn Daly and Alexi Glover ESA Space Environments and Effects Section ESTEC, The Netherlands

Services and associated data collection means should (eventually) be driven by user requirements User Requirements Data Requirements Measurement Requirements System Design

User Needs Identification Parallel studies for ESA by consortia led by Alcatel (now Thales Alenia Space) and RAL ~ 2000: –Intensive study of user requirements, leading to full system designs; More recent updating in context of study of Space Weather Nanosats (RAL at al.) ~ 2006 Consolidation in the scope of ILWS Task Group on “users” (see poster Glover et al., this meeting) Presentation of Hochedez et al, “Monitoring capabilities for solar weather nowcast and forecast”, ESWW 2004 (available esa-spaceweather.net)

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User Requirements Focus on End Effects e.g. RAL study of user requirements:

Solar Sources and Ultimate Effects Service Requirements Active region identification, characterisation and tracking Coronal hole identification and tracking Establishment of active region and coronal hole magnetic fields Warnings of potential flaring and CMEs Alerts on flaring and CME occurrence Event magnitude prediction “All clear” Note timescale differences: –Flare EM in minutes –SEP: ~ hour –Shocks and storms: days Primary PhenomenaResulting phenomena Early phase of coronal mass ejection (CME) Prompt acceleration of energetic particles Interplanetary shock preceding CME Continuing acceleration of energetic particles Magnetic structures associated with CME Affect interplanetary propagation of energetic particles; Trigger geomagnetic storms on encountering magnetosphere; Coronal holesHigh speed streams: Boundaries are sources of acceleration; Boundaries trigger geomagnetic storms; Solar FlaresLarge UV and X emissions affect ionosphere and thermosphere

Measurement Requirements

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1 EUV / X-ray solar images Full Sun images in EUV / X-ray wavelengths are required for precursor identification with angular resolution as good as or better than SOHO EIT, ie. 5 arc seconds. 1–hour resolution is probably adequate. 2 Visible or UV occulted coronal images Coronal images show the occurrence of Halo CMEs. Angular resolution as good as SOHO LASCO, ie. 11 arc seconds, is desired. The good spectral resolution of LASCO is not essential for a Space Weather application. 3 Visible or UV images of Sun-Earth space To spot Earth-directed CMEs, stereo viewing from, for example, Earth and L4 or L5 is preferable, with angular resolution of around 30 arc seconds. 7 X-ray flux 1 minute resolution of total flux is required to capture X-ray flare onset and magnitude. Spectral measurements like those of GOES, ie nm and nm, are required. Higher spectral resolution than the GOES instrument may be useful, eg. 1-20keV spectral measurements which could be achieved using proportional counters or solid state detectors. Detection of solar radio bursts, from the ground in the MHz range, is a possible alternative or complementary measurement. 8 UV flux This parameter is required for its effect on the ionosphere and upper atmosphere. 9 F10.7 radio flux F10.7cm is radio flux from the Sun, usually measured every day at Dominion in Canada. It is often equivalent to SSN. Continuous measurements would require several stations around the globe. 17 SSN SSN is the optical number of sunspots according to the international index for sunspots algorithm. This index is routinely maintained by the World Data Center for the Sunspot Index in Brussels. 18 IMF (B-field) … work on modelling magnetic structures in the solar wind, such as CMEs, has indicated that knowledge of the magnetic field structure of the Sun at the point of origin may enable the field within the structure to be predicted. …

Synthesis of solar measurement requirements

What is done now? ISES services including European ones –Flare prediction and warnings –SPE predictions and warnings –Alert Support Independent access to solar (SOHO, Ground, …) images by system operators without support and interpretation Access to (e.g.) SIDC, CLS by sat. operations NOAA support to human spaceflight via JSC SRAG …

Solar Observations in the Context of Human Space Exploration Future manned missions to Moon/Mars will have strong requirements for forecasts and nowcasts Unpredictability of event timings and magnitude (helio-propagation) US National Research Council Report (2006) Based on Wintergreen workshop (2005) “For the average well-connected event, these methods predict the maximum intensity within an order of magnitude and the timing of the maximum within a couple of hours. These methods, however, fall apart for shock-dominated events. Hence, current forecasting models do badly in predicting extreme events, and extreme events represent the greatest danger to human spaceflight crews.”

Courtesy of Mark Weyland (JSC SRAG)

NASA human spaceflight needs Develop forecasting tools giving 30 minutes to 2 hours lead time (depending on the type of event). Free-space/near-Earth measurements or reliable models of higher- energy (~ MeV) proton/ion spectra. ACE type data/models on mission termination. Be able to predict magnitude / duration / characteristics of SPE from information received at onset of event –Corollary: model predictions for 'all-clear' at onset for small events and/or 'all-clear' forecasting for n day in advance with <~5% probability of particle activity. Improved model correlations/precursors of activity, e.g. electron signatures. Back-side solar imaging/modeling enabling region characterization. Better comparison of instrument readings onboard Shuttle/Station with models transporting simulated or past events through heliosphere / magnetosphere / vehicle and into onboard detectors. Model interpretations allowing correction of GOES particle data to near free-space values.

Research Identify the (reliable) solar surface precursors and indicators of flares and CMEs –Solar magnetic field features –EIT waves and Moreton waves –Helioseismology Magnetic features associated with CMEs and their coupling to heliosphere models in real time Solar Data driven models of heliospheric magnetic field for geoeffectiveness prediction Seeding/boundary conditions of shock and particle models Prediction methodologies (physics based, NN, etc.) Coronal hole characteristics (boundaries, heliospheric extension) → SOTERIA will play a major role in Europe → New measurement requirements will probably emerge

There are Differences between Science Requirements and Service Requirements Data type Resolution Coverage (location, target) Timeliness Continuity Quality (calibration) Solar assets will continue to be Science facilities in short and medium term

Proba-2 LYRA and SWAP are very good precursors for space weather “service oriented” instruments: –Limited resources on a microsat (mass, volume, power, telemetry); –Relatively low development cost; –Demonstrating new technologies (APS, diamond detectors); –Low cost orbit (PEO) operations; –Ground segment aimed to be “rapid, open” Both applications and science sides of space weather look forward to its success

Conclusions User requirements have been extensively studied, but are evolving There are on-going UR capture activities in ILWS If it goes ahead, the ESA SSA phase 1 will include User Requirements consolidation User requirements vary considerably in terms of difficulty: –Among the most challenging is response to fast-onset SPEs Important to maintain links to fast-moving research which are establishing valuable new understanding and methods (e.g. SIDC NEMO) While in the long term service-oriented payloads should be launched, in the medium and short term, users need support of science missions. We look forward to Proba-2