Field map implementation

[Vyacheslav]

Dear Didier,

thus, to use previously obtained results, it still needed to run calculation in the envelope mode.

Is it right?

[Didier]

Dear Vyacheslav,

Yes

Didier

[Vyacheslav]

Dear Didier, one more problem with 3D RF field introduction into project.
Please, check my project (see attachment

ErfField.zip

(366.78 KiB) Downloaded 226 times

) and answer me what is wrong and why program return next messages:

Error.jpg (244.97 KiB) Viewed 3915 times

?
Regards, Vyacheslav.

[Didier]

Dear Vyacheslav,

Plotting your field, I see something very huge explaining why you have this kind of message. Probably you should reduce the ke parameter of FIELD_MAP from 1e6 to 1e-6, perhaps.

field.png (122.11 KiB) Viewed 3912 times

Regards,

Didier

[Vyacheslav]

Dear Didier, unfortunately ke =1 did not help. Error message is still the same. What else can it be?

Problem.jpg (298.05 KiB) Viewed 3911 times

[Didier]

Dear Vyacheslav,

My field map plot has been done off axis with x=y=1mm and already gives Ex,y=10e+12 MV/m, so even with ke=1 it is still huge !
My felling is ke=10e-8, what work on my side with few losses, (Your field map is defined on +/-20 mm, which is smaller than the size of your beam)

Regards,

Didier

[Vyacheslav]

Dear Didier,
please find attached files with FIELD MAP implementation.
My question: does the 4th parameter of FIELD_MAP (R - aperture) have influence on the calculated results?
In the 1st archive, R was set to 9 in accordance with field files whereas it was set to 20 in the 2nd archive.
As it is seen from calculated envelopes there are no any differences.
Is it correct?
Regards, Vyacheslav.

[Didier]

Dear Vyacheslav,

The aperture considered for the calculation of the losses is either the aperture defined in the 4th parameter or the limits defined in your field map when they are lower than this 4th parameter. Here, the maps are on 9x9 mm cubic and the 4th 9 or 20 mm circular. So a priori the aperture used will be almost for all particles those of the dimensions of the field map, but not exactly (circle vs square). By the way, you can see the losses are not exactly the same (27 vs 71)

Regards,

Didier

[Vyacheslav]

Am I right that Ez(x,y,z,t)=Ez(x,y,z)*cos(omega*t-kz*z), where Ez is the field map data value is a correct expression for the right-side of z-motion equation?

Dear Didier,
in this case how is synchronous phase defined? For example, it is need that in every accelerating gap (that is region with nonzero Ez field) synchronous phase will be equal to 45 deg.
If I use SET_SYNC_PHASE and put the 3rd parameter of FIELD_MAP equal to 45, will synchronous phase equal 45 deg all along the cavity?
If not, what shall I do to set synchronous phase as it is described above?

Regards,
Vyacheslav

[Didier]

Vyacheslav,

Your definition of synchronous phase in a multi-gap cavity is not the one in TraceWin. You should read the definition of synchronous phase in the TraceWin manual. It is defined for the whole cavity, which is a bit like defining an equivalence between a thin gap and a multi-gap cavity.

Regards,

Didier