From: Arthur W. Brooks
Sent: Tuesday, July 18, 2006 9:21 AM
To: Michael C. Zarnstorff
Cc: Wayne T. Reiersen
Subject: RE: Candidate Trim Coil Set on MCWF Outer Surface

Attachments: Trim Coil Currents Comparison r1.xls

Mike,

I've added the 99 coil candidate trim coil configuration (located just inside the cryostat and outside the TF/PF) to the attached comparison spreadsheet. The same four sets of targets were considered as in my earlier email (appended below). 

As we suspected, the maximum current demanded by the 99 coil set lie between the 144 coil (outer surface of MCWF) and the original 30 coil set (also just inside the cryostat).

Plots of the coils sets are included on separate worksheets in the attachement.

Regards,

Art

-----Original Message-----
From: Michael C. Zarnstorff 
Sent: Sunday, July 16, 2006 4:45 PM
To: Arthur W. Brooks
Subject: RE: Candidate Trim Coil Set on MCWF Outer Surface

Art,

Given the concern that the project is expressing on the ability to put trim 
coils on the modular coil shell, I think it is time to also take a look at 
the 99-coil set at the outer radius.  Could you please do a similar 
analysis for it?  That will give us some indication of the relative 
importance of the distance between coils and plasma vs. having more finely 
divided trim coils.

Let me know whether you can fit this in your schedule...

thanks.
Mike.


At 12:30 PM 3/8/2006, you wrote:
>Mike,
>
>Attached is a comparison of the trim coil currents required by the two
>sets of coils (original 30 on the cryostat and the more recent 144 on
>the MCWF) in targeting resonances in the m05_e04 plasma. Four different
>calculations were done after generating the coupling matrix for coil
>currents and target resonances:
>
>No Modes Coupled: - Coil Currents required to suppress single resonance
>(magnitude assumed of Bmn = 1.e-4)
>                         (other resonances may be excited)
>All Modes Coupled: - Coil Currents required to suppress single resonance
>while not exciting others
>                         (ie Bmn = 1.e-4 for target, 0. for all others)
>
>Modes to 6,3 coupled: Re All Modes, but reducing number of participating
>modes
>Modes to 5,3 coupled: Re All Modes, but reducing number of participating
>modes
>
>As you can see, the max currents are significantly lower for the 144
>coils and may allow targeting of a wider range of resonaces.
>
>Art
>
>
>
>-----Original Message-----
>From: Michael C. Zarnstorff
>Sent: Friday, January 27, 2006 3:50 PM
>To: Arthur W. Brooks
>Cc: Ed Lazarus
>Subject: Re: Candidate Trim Coil Set on MCWF Outer Surface
>
>Art,
>
>Great!  Thanks very much.  144!
>
>I think the next step (for the resonant fields goals) is to repeat the
>analysis you did for the original engineering set, but with this new set
>to
>determine their effectiveness and sensitivity.  After that, we will have
>to
>decide whether to analyze the outer set of 99 or not.  And then we
>should
>proceed to considering subsets.
>
>I am out at GA next week, but will be on email.
>
>thanks.
>Mike.
>
>
>
>At 03:36 PM 1/27/2006, you wrote:
> >Mike, Ed,
> >
> >I've posted a set of trim coils for physics evaluation at:
> >
> >ftp://ftp.pppl.gov/pub/abrooks/NCSX_COIL_DATA/li383_1.4m/trim/01_26_06/
> >
> >coils.extrim_012606_sym
> >coils.extrim_012606_nosym
> >
> >extrim_012606_sym.ps
> >extrim_012606_sym.pdf
> >
> >These lie on the outer surface of the MCWF and are segmented as we
> >discussed last Friday. There are 8 loops per modular coils (4 top, 4
> >bottom) for a total of 144 trim coils. Coils 1-8 are on the Type A
>MCWF,
> >9-16 on Type B and 17-24 are on Type C, ordered with the lowest number
> >on the bottom inboard and increasing as we go poloidally outward,
>upward
> >and around to the inboard top. I have created two coils files, each
> >containing the same coil geometry, but differing in how they are
> >grouped. The first (*_sym) contains symmetric grouping of coils (24
> >groups with 6 coils in each group). The second (*_nosym) puts each coil
> >in a separate group (numbered 1 thru 144). There are also plot files in
> >pdf and ps formats showing a few views (unfortunately they are very
> >busy). Since coils files are only filaments, I don't have an easy way
>to
> >put them in "eDrawing" format yet.
> >
> >The coils are all given a nominal value of 1000. amps. The positive
> >current sense is such as to always produce a positive radial field
>(away
> >from plasma axis).
> >
> >These coils will need to shrink or otherwise morph at some point to
> >clear hardware and other obstructions, but should serve as a reasonable
> >representation for concept exploration.
> >
> >Art
>