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Usage of the Cluster Data in ILWS Studies

Harri Laakso, Philippe Escoubet, Matt Taylor, and Arnaud MassonEuropean Space Agency (ESA)

Science and Robotic Exploration DirectorateNoordwijk, The Netherlands

ILWS 2009, Ubatuba, Brazil, 4-9 October 2009

Contents: Introduction to Cluster observations Introduction to Cluster data archive*

* An ESA contribution to the ILWS

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Introduction to the Cluster Mission Cluster is a four-satellite constellation mission where the

satellite separations are controlled and varied between 100 – 10 000 km

The satellites are on a polar-orbit with the orbital period, perigee distance and apogee distance of 55 hours, <4 Re and 19 Re, respectively

The spacecraft were launched in summer 2000 and the science operations started on 1 February 2001. The mission has been extended until December 2012

The key dayside investigations: solar wind, bow shock, magnetopause and cusp

The key nightside investigations: auroral zone, plasma sheet, radiation belts and plasmasphere

Two Cluster workshops are organized annually: there are usually 100+ participants and are open to all scientists, for details, see

http://caa.estec.esa.int/wksp/cluster_workshop_home.xml

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Cluster InstrumentsParticle experiments:

PEACE Thermal electrons with energies <30 keV

CIS Thermal ions (including composition) below 40 keV

RAPID High energy electrons and ions below 450 keV (Ei>10 keV, Ee>20 keV)

EDI Plasma drift velocity and DC electric fields, with electron beam injection

ASPOC Spacecraft potential control, with ion current emission

Fields & waves experiments:

FGM DC magnetic fields at 22 Hz (66 Hz in burst mode)

EFW DC electric fields at 25 Hz (450 Hz)

STAFF Magnetic and electric fluctuations <4 kHz (use search coil & EFW sensors)

WHISPER Electron density (0.1-80 cc) and plasma waves (2-80 kHz)

WBD Electric field waveforms <500 kHz

DWP Wave processor and wave-particle correlator

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Polar cusp

Solar wind

Auroral zone

Magnetopause

Cluster Orbit in March-April

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Cluster Dayside Observations

Auroral region

Polar cap

Cusp

Dayside magnetosphere

Magnetosheath

Solar wind

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Cluster Orbit in September-October

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Cluster Nightside Observations

Radiation belts/plasmasphere/

cusp

Lobe

Plasma sheet

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Solar wind

Auroral zone:Acceleration region2001

2008-2009

Magnetopause:subsolar point

Cluster Orbit Evolution 2008 -

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Solar wind

Near Earth tail:Current disruption

2001

2008-2009

Low altitude cusp

Cluster Orbit Evolution 2008 -

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The Cluster Active Archive CAA (http://caa.estec.esa.int/) aims to ensure that

The CAA will contain all Cluster high-resolution data as well as all allied (supporting) data products necessary to the full interpretation of the full-resolution datasets

the entire high- and low-resolution datasets are fully calibrated (to the level achievable within the limited resources available)

the data should be suitable for science use and publication by the world-wide scientific community

all data are provided in a standard format (CEF - Cluster Exchange Format) and with a complete set of metadata in machine readable form

the CAA will provide user friendly services for searching and accessing these data

What is CAA?

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CAA Organigram-2009

Cluster Project Scientist(M Taylor)

Deputy(A Masson)

Project Manager(H Laakso)

Technical Manager(C Perry)

Working Groups(Chairs: C Harvey, A Allen)

System Engineer(R Turner) ESOCJSOC

PI: K Torkar

E Georgescu

PI: R Torbert

E Kronberg

PI: P Daly

A Barthe

PI: I Dandouras

N Doss

PI: A Fazakerley

S Walker

PI: H Alleyne

C Burlaud

PI: N Cornilleau-Wehrlin

PI: J Pickett

P French

PI: E Lucek

C Cully

PI: M Andre

G Facsko

PI: J-G Trotignon

Note: names in red color are contractors supported by the CAA project

Archive Developers(S McCaffrey, D Herment, J. Kissi)

CISASPOC EDI RAPID DWP EFW WBDFGM STAFF WHISPERPEACE

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The coverage and range of products are being continually improved, currently with over 200 datasets available from each spacecraft, including

high-resolution DC and AC B- & E-fields full 3D electron & ion distributions for 0 eV - 400 keV various ancillary & browse products

Most/many of the teams have provided the data files for years 2001-2007

a number of complicated products, mainly due to calibration difficulties, are still partly missing

currently the teams are producing and delivering files for year 2008

Status of the CAA Data Inventory

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CAA Access Point

The CAA operational since Feb 2006

Registration is necessary in order to have an access to the data and graphical products

http://caa.estec.esa.int/

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Data Downloading

Two access routes to the data:

xml forms interface on the CAA web site

Command-line interface to automated download requests

Data selection can be based on spacecraft, experiment, measurement type, instrument type and/or time range

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User Profiles

Request can be stored as user profile to speed up subsequent requests:

provide an easy way to set-up and request standard selections from the large number of available CAA datasets.

can be used for machine accessible interface

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Command-line Request Simple way of requesting data from the CAA database

Example: requesting a month of full-resolution FGM data from Cluster 1 in February 2001 in daily files in cdf format, one types

wget "http://caa.estec.esa.int/caa_query/?uname=username&pwd=password& dataset_id=C1_CP_FGM_FULL&time_range=2001-02-01T00:00:00Z/2001-02-28T24:00:00Z&file_interval=1day&file_format=cdf"

one can also download files ingested into the system after a given day: ingestedsince=2008-01-01T00:00:00Z &

Details/definitions of using the tool are described in a user guide (available under Documentation)

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CAA User Activity

CAA has ~920 registered users

Every month ~150 different users log in the CAA

Every month CAA gets ~20 new users

The total data volume downloaded is ~0.5 TB per month

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• These plots are produced by CAA using the calibrated CAA data products

• User can select and arrange individual panels

• Selected set can be saved as a user profile

• Plots on screen are in png whereas the downloaded plots are in ps

CAA Graphics

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Pre-generated CAA plots based on the CAA database

1-hr, 6-hr and 24-hr plots are available

CAA Graphics

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provided by the instrument teams and the CSDS (CSDSweb) quick-look system

not well calibrated i.e. not suitable to science Plots useful for event identifications

links to the database selection interface with the time pre-selected based on the current plot interval

Quick-Look Plots, 1

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Quick-Look Plots, 2

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New GUI For Downloading

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New GUI For Downloading

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Activity: observations from different Cluster instruments are compared in detail both statistically and on event basis. This is essential to the the production of high-quality data products. Minutes and presentations of the past workshops can be found at http://caa.estec.esa.int/caa/cross-cal.xml

The following workshops have been organized:

CAA Cross-Calibration Workshops

•Kick-off Cross-Cal Meeting ESTEC, Netherlands 23 Sep 2005 •1st Cross-Cal Workshop ESTEC, Netherlands 2-3 Feb 2006•2nd Cross-Cal Workshop ESTEC, Netherlands 16 May 2006•3rd Cross-Cal Workshop MSSL, London, UK 26-27 Oc 2006•4th Cross-Cal Workshop LPCE, Orleans, France 12-13 Feb 2007•5th Cross-Cal Workshop ESTEC, Netherlands 14 May 2007•6th Cross-Cal Workshop Imperial College, London, UK 24-25 Oct 2007•7th Cross-Cal Workshop Tenerife, Spain 9 Mar 2008•8th Cross-Cal Workshop Kinsale, Ireland 28-30 Oct 2008•9th Cross-Cal Workshop Cambridge, UK 25-27 Mar 2009•10th Cross-Cal Workshop Paris, France 2-4 Nov 2009

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Documentation

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CEF FORMAT

All the science-quality digital data products are provided to the CAA in a standard representation, the Cluster Exchange Format (CEF)

Full descriptions of the data format and meta-data standards used by the CAA can be accessed from the documents area of the CAA web site

http://caa.estec.esa.int/caa/documentation.xml

The CEF

is an ASCII, comma separated, tabular format supporting multi-line records

has a fully self-describing header

offers straightforward long-term accessibility to the Cluster data

On download, products can optionally be converted to the widely used NASA Common Data Format (CDF)

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Software MATLAB & IDL tools for reading and

displaying data in CEF-format

QSAS for reading & displaying CEF data

Instrument team software for displaying their data

etc

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Cluster is a four-satellite constellation mission: Cluster science: detailed investigations of physical processes in space

plasmas around the Earth Single satellite observations can be very valuable for global magnetospheric

studies, e.g., in the spring-time the spacecraft stays in the solar wind ~24 hours every few days, or in the autumn-time similarly in the plasma sheet

The Cluster observations are available since 1 February 2001

All full- and spin-resolution Cluster data available to the world-wide science community through the Cluster Active Archive CAA (http://caa.estec.esa.int/) All data are aimed to be well calibrated (done with limited resources) all data are provided in a standard format (CEF - Cluster Exchange Format)

with a complete set of metadata in machine readable form All data can also be downloaded in CDF format Currently there are about 20-30 TB of data in compressed format If there are any issues on the usability and quality of the data products, one

can contact the CAA by sending an e-mail to caateam@rssd.esa.int, or filling in a feedback form at http://caa.estec.esa.int/caa/feedback_intro.xml

Summary