The Coronal Solar Magnetism Observatory (COSMO)

High Altitude Observatory (HAO) – National Center for Atmospheric Research (NCAR)

The National Center for Atmospheric Research is operated by the University Corporation for Atmospheric Researchunder sponsorship of the National Science Foundation. An Equal Opportunity/Affirmative Action Employer.

The Coronal Solar Magnetism Observatory

(COSMO)

Steven Tomczyk COSMO 23 April 2013

Motivation

Our Vulnerability to Space Weather is Increasing

Manned Space Flight Power Grids Communications GPS Navigation


In response to society’s need to reduce our vulnerability to Space Weather, the goals of COSMO are to:

Understand processes that lead to solar eruptions

Support development of predictive capability

Monitor real-time eruptive events

Estimate event geo-effectiveness

COSMO Goals


Requirements

Solar activity is Magnetically Driven

Progress requires measurement of:

Strength and direction of magnetic fields in the Solar Corona, Chromosphereand Photosphere

Plasma propertiesVelocity, Temperature, Density

Need Systems Approach

LASCO


COSMO is a proposed facility dedicated to studying solar magnetic fields and their role in driving solar activity such as coronal mass ejections Synoptically. It comprises:

1.5 m Aperture Coronagraph (Corona)

Disk Imager / Polarimeter - ChroMag (Chromosphere/Photosphere)

K-coronagraph (CME)

1.5-m coronagraph pictured here

COSMO


K-Coronagraph

Measures coronal structure and evolution

Observes Coronal Mass Ejections in real-time

Observes shocks which produce energetic particles

Fully funded ($2.2M, NSF special), construction nearly complete, deployment to MLSO late Summer


Chromosphere and Prominence Magnetometer (ChroMag)

ChroMag will make complete-Stokes observations of the entire solar disk at high temporal cadence in many spectral lines (587 - 1083 nm) that can be used to accurately infer the magnetic field and other plasma parameters from the photosphere through the chromosphere.


ChroMag - Tunable Filter


1.5 m refractive coronagraph

1º field-of-view

Low scattered light

Synoptic operation

Will obtain measurements ofCoronal B with 1 Gauss precision in 10 minutes, 5 arcsecond spatial resolution

COSMO Large Coronagraph

Would be largest refractive telescope in the world, $20M


COSMO LC Design Drivers

Large aperture– Need to collect photons (V/I ~ 10-4 / Gauss)

Low scattered light– Lens better than mirror (microroughness and dust)

High efficiency - no reflections– ATST 10, EST 14 reflections before coude instruments

Symmetrical on-axis optical system - Makes polarimetry easier

Large Field-of-View - Coronal structures are large - aberrations are easier to control with a lens than a mirror

Pressurized Dome Design – HEPA filtering - maintain cleanliness


LSST will have a 1.6 m diameter lens and a 1.1 m lens!

LSST has unique combination of aperture and FOV Étendue light collecting power = collecting area x solid angle FOV = 319 m2 deg2

Large Synoptic Survey Telescope


The COSMO coronagraph will have a light gathering power (étendue) that exceeds that of the ATST by a factor of 15.

COSMO is Highly Complementary

Most existing and planned solar telescopes have small FOV, will observe at high spatial resolution and are not synoptic.

Sun

ATST FOV

COSMO FOV

Sun

Offset Mode


COSMO LC Status

COSMO Large Coronagraph Conceptual Design, Feasibility Study Complete

COSMO Now an International Project – US/China Collaboration on Design Development

Preliminary Design Review – Feb 2014

Submit Proposals to Chinese and US Agencies for Construction of 2 Large Coronagraphs

COSMO Endorsed by 2012 Heliophysics Decadal Survey

Documents

The Coronal Solar Magnetism Observatory (COSMO)