SOI-MDI Newsletter

Number 5: April 1994

IN THIS ISSUE:

• Team Meeting (in conjunction with GONG meeting, Los Angeles)
• Preliminary Team Meeting Agenda
• Working Team Reports
• NASA Award Presentation
• Announcement of Team Meeting At Fallen Leaf Lake in October

Calendar

1994

• April 28 - Delivery of MDI instrument to MMS-UK.
• Ap. 28-May 5 - Bench testing of MDI
• May 6 - Mechanical integration
• May 9 & 10 - Electrical integration
• May 11-17 - Functional testing
• May 15-20 - SOI-MDI Team Meeting, Los Angeles.
• May 16-20 - GONG Meeting, Los Angeles.
• October 9-12 - SOI-MDI Team Meeting, Fallen Leaf Lake, CA.

1995

• April 2-6 - SOHO Workshop, Asilomar Conference Center, Pacific Grove, California.
• July 27 - SOHO launch

From the Project Office

Phil Scherrer, Stanford

If all goes according to the current plan, the MDI instrument will have been integrated onto the SOHO Payload Module by the time of the GONG-94 meeting. This is a time of a shift in our primary activities from the development and testing of MDI to final development and testing of the analysis programs for the SOI investigation. If the SOI investigation is to fulfill its promise we must be prepared to process the data through to physical interpretation by the time we begin to have real data in the early fall of next year.

The SOI team meeting will be interwoven into the GONG-94 meeting to allow several of the SOI Team Science Working Groups to meet on Sunday afternoon and during the week. We will have a full team discussion and summary of the working group progress on Friday after the regular GONG meeting. I ask you all to please be prepared to participate in these working groups to both insure that your perspectives are taken into account and to help do the work.

This is also the time that we are preparing the proposal for the MO&DA (Mission Operations and Data Analysis) phase of the mission. This is a good time for all Co-Is as well as the Stanford and Lockheed groups to review their plans and needs for the mission. We will be asking all Co-Is who expect funding during the next several years to prepare proposals in June or July. The date will be driven by NASA needs and will be determined by the time of the GONG-94 week. I would like to discuss your plans during the meeting.

The present word from NASA is that we will be funded for MO&DA at a lower level than we had expected several months ago. Given the general NASA funding situation, this is not a surprise. We are still studying the impact of the likely 15-20% reduction. This makes it even more important for each of you to make real estimates of the support levels needed to accomplish the SOI investigation

SOI-MDI Team Meeting

For information about housing at USC, and about plans for the GONG meeting, please contact Tricia Diamond, tdiamond@ra.usc.edu, 213-740-5848.

For further information about the SOI-MDI Team Meeting, contact Margie Stehle, mstehle@solar.stanford.edu, 415-723-1505.

Preliminary Agenda: SOI-MDI Team Meeting

3:00 pm - 5:00 pm Inversions Working Team (SOI/GONG)

5:00 pm - 8:00 pm GONG Registration

7:30 pm - 9:00 pm GONG Meeting Reception

Monday, 16 May 1994

Tuesday, 17 May 1994

11:00 am - 12 noon Peak Bagging Working Team (SOI/GONG)

11:00 am - 12 noon Low Frequency/Steady Flows (GONG)

4:00 pm - 5:00 pm Data Reduction and Analysis (GONG)

4:00 pm - 5:00 pm Mode Physics (GONG)

7:00 pm - 9:00 pm GONG DMAC Users Committee

Wednesday, 18 May 1994

morning MDI Instrument Status Report (as part of GONG meeting)

Thursday, 19 May 1994

11:00 am - 12 noon Ring Analysis Working Team (SOI)

11:00 am - 12 noon Magnetic Effects (GONG)

4:00 pm - 5:00 pm Active Region Seismology Working Team (SOI)

4:00 pm - 5:00 pm GONG Site Reps

Friday, 20 May 1994

1:00 pm - 3:00 pm SOI Team Plenary Session

Working Team Reports

As far as data acquisition is concerned, MDI is in a position to observe at higher resolution, over longer times, and with better monitoring of changes in the magnetic field than the ground based observations which have been so stimulating over the past several years. In the area of data analysis, some issues we brought up which certainly require more discussion are: how to measure phase shifts, how to look for discrete sources, or ``pings,'' time-distance helioseismology, how to measure and interpret the excess high frequency power seen around active regions, how to measure frequency shifts of high degree modes in regions of strong field.

The campaign modes written to date are:

1. Atmospheric g-modes

2. Seismology of plage regions

3. Surface amplitudes of p-modes

4. Active region tomography: absorption coefficients and phase shifts

5. High frequency observations

- Ellen Zweibel

Coronal Magnetic Field Science Team

This team currently consists of Todd Hoeksema, team leader; Xuepu Zhao, local coordinator; Sasha Kosovichev and Roger Ulrich. The immediate task of the team is to define the processing needed to model the coronal magnetic field from the MDI photospheric observations in a way that is useful for our own scientific investigations and for collaborative efforts with other SOHO experiments.

No formal team meeting is planned for May, but I hope we can get together informally over lunch, perhaps together with the Magnetic Field team, to discuss how this group should function. Please contact todd@solar if you would like to join this team or if you have ideas about what should be done. A preliminary description and development schedule is available upon request.

- Todd Hoeksema and Xuepu Zhao

GOLF Magnetic Effects Correction

The magnetic proxy to be provided by the SOI instrument for use by the GOLF investigation has undergone some revision this spring. The analysis published by Ulrich et al. (Astron. and Astrophys. 280, 268, [1993]) makes it clear that it is essential to distinguish between strong and weak field regions of the solar surface. The former are part of sunspot regions while the latter are part of plage regions. While both types of region can influence the measurements to be made by both the GOLF and SOI instruments, the inter-relationships are different in the different types of region. A proper analysis thus requires at least two observables in order to permit a determination of this population type. The small scale of the sunspots compared to the plage regions makes it important to have better spatial resolution than was previously thought necessary. The current plan is to obtain the magnetic proxy as previously defined along with a line core intensity from I2+I3. The data are boxcar averaged spatially down to a 102 by 102 square array which is then temporally averaged with a trapezoidal taper with a sampling duration of 25 minutes. The taper runs linearly from 1 at tc \xb1 9 minutes to 0 at tc \xb1 12 minutes. The weighted averages are sampled once every 20 minutes for telemetry.

Problems remaining:

1. The two parameters depend on position on the solar disk in a complicated manner due to differential rotation, limb shift, limb darkening and a variety of instrumental response function effects. The tuning of the center point of the MDI filter also affects the dependencies. All these effects need to be measured and modelled.

2. Quantitative relationships between the observable parameters and the GOLF measurement need to be established on the basis of actual solar observations. As we move into the time of sunspot minimum, the study of active region effects becomes more difficult due to the scarcity of spot regions.

3. The trade-off between spatial and temporal resolution can still be modified although the time for making firm decisions is nearly past. It is only because our basic plan is in place that we can think about making changes that primarily affect software.

- Roger Ulrich

Limb Figure Team

Current team members: P. Milford, J. Kuhn, L. Sá and H. Hudson.

Based on techniques and code developed by J. Kuhn and T. McWilliams, outlined in SOI-TN-049, SOI-TN-050, and SOI-TN-051, we have been studying a short timeseries of Yohkoh white light data. Though not identical to SOI data, we feel it provides the first true test of the techniques and will enable a more accurate estimate of the signal to noise for space based limb measurements.

Future work will include study of a second Yohkoh data set; a larger dataset at lower observing cadence.

Based on the existing algorithms, currently coded in Fortran, Luiz Sá will be recoding the existing Fortran programs in 'c'. The existing 'under development' Fortran programs, with the original author no longer available, have been a challenge to decide how to integrate into the SSSC pipeline, which is currently very much a 'c' oriented system. To be easily portable to the pipeline, Fortran programs must be carefully coded, with 'science' routines separate from I/O and sequencing routines, as the simplest way to redo the Fortran program is to make a 'c' main program which contains the sequencing, parameter passing and all I/O, which in turn calls the Fortran subroutine. This is also related to how the subroutines will parallelize, an important part of the pipeline processing.

- Peter Milford

Magnetic Fields Science Team

This team currently consists of Todd Hoeksema, team leader and local coordinator, Tom Berger, Rick Bogart, Sasha Kosovichev, Valeri Kotov, George Simon, Alan Title, and Roger Ulrich. Katie Scott is the responsible programmer for magnetic field analysis. If you would like to become an active member of this team, please contact todd@solar.

Over the next few months we will be working to define magnetic field observing sequences; the pipeline processing to be applied to magnetic field observations, including calibration, mapping, and construction of synoptic charts; and the development of related data sets, such as magnetic proxy data, ground-based correlative data, and so on.

Evaluation of test data obtained over the last few months suggests that the magnetic field observations will be reasonably good, though the sources of noise inherent in the MDI ground-based measurements limit our capability to place anything but upper limits on MDI's performance. A report summarizing the analysis of the magnetic observations to date is available upon request.

We have not scheduled a group meeting in May, but I hope we can get together there, at least informally, to discuss our scientific goals for this part of the project. I hope the team can have some meaningful discussions at the October team meeting at Fallen Leaf Lake. If you have inputs for the team or suggestion about how the team should function, please contact me.

- Todd Hoeksema

Peak Bagging and Inversion

Dear Peak Bagging and Inversion Team:

As you should all know by now we plan to meet just before and during the GONG meeting. One purpose is to make sure that what we implement at Stanford makes sense. For this I would like for us to discuss the current plan, the experience of those who have analyzed similar datasets before, and for the theoreticians to tell us which methods we should really be using. If you have any comments on these subjects please bring material for a short presentation. It would be useful if you could let me know in advance if you plan to present something.

Some questions to consider:

Peak bagging: We plan to use my peak fitting method for at least a major part of the l-n diagram. We have not made the final decision for what to use at high l and high n. What do you think? Which other methods should we consider implementing? Some sort of ridge fitting? Do you have software you want to integrate into our processing? How high should we go in l? What about individual splittings versus a-coefficients?

Inversions: We plan to use (at least) a 2-D regularized least squares method. Do you want us to consider other methods? Which? Are there issues you feel we need to address. What should we do for high l modes which are likely to sample a range in l? How about correlations between m's?

- Jesper Schou

Rings Analysis

Team Members: P. Milford, F. Hill, D. Haber, J. Patrone, J. Toomre, K. Julian, D. Gough.

The rings analysis SSSC support project is slow to start due to time constraints. We hope to begin some time after the GONG meeting. Frank Hill has kindly offered all their existing ring analysis software.

We have a one hour meeting scheduled during the GONG meeting to discuss the SOI ring analysis. This is after a review talk by Frank Hill.

Some things to discuss during our 1-hour get together:

A) Juri Toomre is willing to host us for a brief (1 week) ring team meeting in Boulder during the summer: suggested dates are around mid July to late August. A number of people will be in residence and a few of us will be able to visit. We should set a firm date. We should perhaps aim for a few hours at the Fallen Leaf Lake meeting. And perhaps a bit longer 6 months later. Aim to have 1 week again in following summer, perhaps at Stanford, with working prototype ring analysis software in the SSSC.

B) Who is working on what currently.

C) Who is planning to work on what.

D) Test datasets. Real datasets available.

E) Ultimate limits on resolution. Higher spatial resolution.

F) Other inversions than flows.

G) Should we aim to analyze campaign data organized as 3 days of 8 hour data? Or aim to only use contiguous 8 hour or 3-60 day datasets?

H) What SOI resources available for the ring analysis.

I) What must get done/what will not get done?

- Peter Milford

Surface Flows Science Team

The surface flows science team will not be meeting during the GONG meeting. We intend to hold a meeting in conjunction with the SOI/MDI Team Meeting this fall.

- Neal Hurlburt

Another New Baby!

Allison Margaret Hoeksema

Allison arrived on March 29 at 4:49 pm to join the family of Todd and Carole, Nathan and Emily Hoeksema. She weighed in at 9 pounds 10 oz (4.36 kg) and was 20" long (51cm). She and her whole family are doing fine (Emily, age 2, hasn't quite figured things out yet). Todd reports that Allison is regularly sleeping 4-5 hours at a time.

Letter to the Editor

To Whom It May Concern:

The SOI-MDI news, iss. Feb. 94 reported in a very lively manner the `boomerang' journey of MDI to MMS-UK and back after completing its AIV activities.

I appreciate very much the way in which this news keeps the MDI team and the scientific community updated with the latest MDI developments and could only encourage other SOHO PI's to follow the same approach.

I believe however that in all fairness to our contractor (MMS-UK), I must bring to your attention and put in its true perspective the statement made on `preparatory work' by MMS-UK.

In reality MDI inputs (120 new control files) were delivered at a much later date than the one required by MMS and thus requested additional manpower to be put in the job, to the extent even of taking people off other experiment tests in an utmost attempt to complete this extra work.

Nothing is ever perfect, but one must recognise that in this particular case MMS-UK responded with a very positive and constructive attitude deserving therefore credit for what they did in order to support MDI AIV activities.

C. Berner
SOHO Payload & AIV Manager

NASA Awards Presented to Lockheed & Stanford MDI Teams

On March 29, Kenneth O. Sizemore, ISTP Project Manager at Goddard, visited the Hansen Experimental Physics Lab at Stanford and the Solar and Astrophysics Lab at Lockheed to present award plaques to more than 45 MDI team members. Dario Galoppo, Instrument Systems Manager at GSFC, also attended the ceremonies, and stayed for several working days afterwards. Sizemore's visit had the sole purpose of meeting and expressing his appreciation to the MDI team members at Stanford and Lockheed for their fine work. Both ceremonies were well attended, including, at Lockheed, many team members who have moved on to other jobs. Dr. J.B. Reagan, Lockheed VP & General Manager of R&DD, and Project Manager Jake Wolfson spoke on behalf of LPARL, and Principal Investigator Phil Scherrer represented Stanford. The plaques read as follows:

``NASA's Goddard Space Flight Center and the International Solar-Terrestrial Project express their deep appreciation to [Name] for contributions made to the Solar and Heliospheric Observatory. The precision measurements of the Sun's internal dynamics and coronal structure by the Michelson Doppler Imager Flight Model will greatly advance the knowledge of Sun-Earth interactions. Because of your tireless efforts to the MDI Flight Model Instrument, you have earned the recognition and appreciation of the entire SOHO team.''

Fallen Leaf Lake in October!

It looks as if we will have about 42 SOI team members, plus quite a few spouses and children, in attendance!

The cost for participants is $425. This includes three nights' lodging (Sunday through Tuesday nights), all meals from Sunday dinner through Wednesday lunch, an opening-night reception, taxes and gratuities, use of all recreational facilities, and all conference materials. The charge for spouses for the same period is $200. Children from 0-2 years will be charged $50; 3-7 years, $90; 8-10 years, $125; and 11-14 years, $160. Cribs are available. We may also be able to arrange child care, at additional cost, if enough interest is expressed.

Fees may be paid in advance, or at registration. We must guarantee a number to the Sierra Camp on August 10, so please notify us before that date if you have told us you will be there and you find you are NOT going to be able to come. h

Technical Notes

(for a listing of previous Tech Notes, see the SOI-MDI Technical Documents page)

SOI-TN-104      Bogart  	Naming of Datasets for SOI

SOI-TN-105      Aloise et al    Preliminary SSSC Conceptual Design

SOI-TN-106      Bogart et al.   The SOI Program Development Environment

SOI-TN-107      Bogart  	Programming in the SOI Analysis Environment

SOI-TN-108      Bogart & Bacon 	The SOI Analysis Library

SOI-TN-109      Aloise et al.   SSSC Implementation Version 1.0

SOI-TN-110      Scherrer        MDI IP Velocity Algorithm

SOI-TN-111      Bogart  	An Atlas of MDI Ground Test Images (not available by mail)

SOI-TN-112      Scherrer        Use of Data Set Names

SOI-TN-113      Hoeksema        SOI-MDI Magnetic Field Observations

Last Modified: 12 February 1996