Reviewing the Summer School Solar Labs

Nicholas Gross

Background

• Target Audience is 1st year graduate students• Excellent set of activities

using research quality materials

• Developed independently with little coordination

• Sequencing sometimes rough• Developed on multiple platforms

Minor Renovation

• Separate goals so labs build on one another

• Group related activities

• Use uniform platform (CISMDX) where appropriate

• Introduce guided inquiry questions

• Continue to include most resent research findings and professional tools

Today’s Mission

• Identify fundamental concepts that students should have after attending the summer school

• Continue to evolve the summer school material to reflect the latest research findings and tools.

Solar Labs

• Solar Labs– Lab 2: Structure of the near Solar Magnetic Field– Lab 3: Sources of the Solar Wind– Lab 4: Heliospheric Structure– Lab 5: Evolution of Coronal Mass Ejections

• Holistic Goal– Study the structure and evolution of the solar

corona and solar wind and their role as drivers of geospace processes.

Lab 2: Structure of Near Solar Magnetic Field

• Overall Goal: Holistic understanding of solar magnetic field at various phases in the solar cycle

• Activity 1: Use synoptic maps to study the structure of active regions at various phases in the solar cycle.

• Activity 2: Use MAS results to visualize the magnetic field structure at various phases in the solar cycle.

Lab 2: Structure of Near Solar Magnetic Field

• Goal 1: Structure and Evolution of Active Regions– White light vs. magnetogram– Magnetograms from rotation

to rotation– Magnetograms over the solar cycle– Magnetograms from

one cycle to the next

Lab 2: Structure of Near Solar Magnetic Field

• Goal 2:Structure of solar magnetic field during solar minimum– Br = 0 contour is simple

– Closed field lines connect across these contours– Closed lines confined to

lower latitudes near the sun– Open field lines originate

near poles– Open field lines separated

by a current sheet

• Goal 3: Compare the structure of the solar magnetic field at solar minimum and solar maximum. – Br=0 contour more complicated for solar maximum – closed and open field lines can originate from almost

anywhere – Close field lines still do not

extend far from the sun– Open field lines still

separated by a current sheet– Solar Max Current sheet

is far more complicated

Lab 2: Structure of Near Solar Magnetic Field

Lab 3: Sources of the Solar Wind

• Overall Goals– Students will be able to identify the likely sources of

fast solar wind. – Interpret the coronal hole maps generated by WSA

run at SEC.

Lab 3: Sources of the Solar Wind

• Goal 1:Relationship between photospheric magnetic field and coronal hole structure – compare synoptic magneto-grams and EIT images – observe that coronal holes with areas away from active

regions – differences between the coronal hole structures at solar

minimum and solar maximum– polar coronal holes common during solar minimum– coronal holes at lower latitudes likely at solar maximum – open field line foot points occur at coronal holes

Lab 3: Sources of the Solar Wind

• Goal 2: Relationship between coronal hole structure, open field lines, and solar wind speed

– Slow solar wind is observed near the current sheet while fast solar wind is observed away from the current sheet.

– Parcels of solar wind at 5 solar radii can be traced back to a particular coronal hole on the sun.

– Solar wind near the current sheet originates nearer the edges of coronal holes.

– Solar wind away from the current sheet originates nearer the middle of the coronal holes.

Lab 3: Sources of the Solar Wind

Lab 4: Heliospheric Structure

• Overall Goal: Students will explore structures in the solar wind including changes with distance, variation in the azimuthal direction, and properties of co-rotating interaction regions.– Activity 1: Use visualization and line plots to explore

the variations with distance and latitude. – Activity 2: Use visualizations and line plots to explore

variations across CIR boundaries.

Lab 4: Heliospheric Structure

• Goal 1: Radial flow with parameters that vary with distance from the sun.

– density and magnetic field strength decrease as roughly 1/r2 – Velocity is radial and roughly constant with distance from the

sun out to 1 AU.– relate the last two observations to the continuity equation and

frozen in flux – explore the temperature profile and relate it to the equation of

state

Lab 4: Heliospheric Structure

• Goal 2: Solar wind speeds vary with latitude in a way that changes depending on the solar cycle phase. – solar minimum the solar wind is

highly structured with fast solar wind at the poles and slow solar wind near the solar equator

– solar maximum, the solar wind is less ordered, on average being isotropic

Lab 4: Heliospheric Structure

• Goal 3: Properties of Magnetic field segment structure and Co-rotating Interaction Regions (CIR’s)– Existence of Magnetic Segments

and CIR’s– Relation between magnetic segment

boundaries and CIR’s– CIR’s involve interaction of fast

and slow solar wind– Evidence for shocks at CIR boundaries

• Change in velocity • Change in density• Change in magnetic field

Lab 5: Evolution of Coronal Mass Ejections

• Predict arrival time of a CME from white light corona images– Activity: Use difference coronagraphs to

estimate the velocity of CME and its arrival time

• Explore structure of CME at solar minimum and solar maximum– Activity: Use simulation results to visualize

evolution of CME structure as it travels from the sun

Lab 5: Evolution of Coronal Mass Ejections

• Goal 1: CME arrival time can be predicted form difference coronagraphs.– A “halo” CME is the result of a CME

launched almost directly towards Earth.– The expansion rate can be used to

estimate the launch speed of the CME– The speed is filtered by an average

acceleration due to the solar wind conditions that the CME evolves in.

Lab 5: Evolution of Coronal Mass Ejections

• Goal 2: CME evolves differently depending on the phase of the solar cycle– CME flattens as it moves out from the sun– Solar wind structure affects the evolution of the CME– CME launched during solar maximum is isotropic– CME launched during solar minimum has a strongly

varying azimuthal structure.

Way Forward

• Questions and Feedback?

• Review summer school materials and adjust tools and manuals accordingly

• Feedback to gross@bu.edu

• Volunteers?