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| jartok | Hi All,
Has anyone used MMS data to find null points using plasmapy.analysis.nullpoint.null_point_find?
Or may be someone has some idea how it might be done?
I have a bunch of numbers for x, y, z position (in GSM coordinates) of the MMS spacecraft (SC),and I have corresponding magnetic field values; Bx, By, Bz.
I have 4 data files, one for each SC.
Q Part 1:
As far as I can see, I only find one set of data is provided to the plasmapy.analysis.nullpoint.null_point_find function.
(Ref: https://docs.plasmapy.org/en/stable/notebooks/analysis/nullpoint.html
the second example, "Arbitrary regular grid")
It looks like there are two points P1 (5, 5, 5), and P2 (6,6,6).
So the coordinate arrays to pass to the null_point_find function is:
[x1, x2], [y1, y2], [z1, z2], that is, [5,6], [5,6], [5,6]
Then one needs to pass [Bx1, Bx2], [By1, By2], [Bz1, Bz2].
In the example, Bx1, Bx2 both are [-0.5, -0.5], [0.5, 0.5].
My question is how do I interpret this "[-0.5, -0.5], [0.5, 0.5]",
I mean, in my case I only have one single float value for Bx1 (eg.1.3665584), and another float value for Bx2.. etc.
Should I pass what I have ( the single float value above)?
(I did pass single float values, and the program didn't crash, but it didn't give a right answer either...see part 3)
Q Part 2:
My understanding is that all four MMS SC are used to locate null points in the magnetosphere.
Then, how do I pass 4 different datasets to this function?
Should I do something like, pass data from one SC at a time, and see they all find the null(s) at the same location?
Q Part3:
I passed some other data (than what is used in the example), but still I get the same answer as the example.
Is this code working for other?
Could it be that this code is still in development?
Thank you for reading this long post. | 17:54:34 |
| jartok | * Hi All,
Has anyone used MMS data to find null points using plasmapy.analysis.nullpoint.null_point_find?
Or may be someone has some idea how it might be done?
I have a bunch of numbers for x, y, z position (in GSM coordinates) of the MMS spacecraft (SC),and I have corresponding magnetic field values; Bx, By, Bz.
I have 4 data files, one for each SC.
Q Part 1:
As far as I can see, I only find one set of data is provided to the plasmapy.analysis.nullpoint.null_point_find function.
(Ref: https://docs.plasmapy.org/en/stable/notebooks/analysis/nullpoint.html
the second example, "Arbitrary regular grid")
It looks like there are two points P1 (5, 5, 5), and P2 (6,6,6).
So the coordinate arrays to pass to the null_point_find function is:
[x1, x2], [y1, y2], [z1, z2], that is, [5,6], [5,6], [5,6]
Then one needs to pass [Bx1, Bx2], [By1, By2], [Bz1, Bz2].
In the example, Bx1, Bx2 both are [-0.5, -0.5], [0.5, 0.5].
My question is how do I interpret this "[-0.5, -0.5], [0.5, 0.5]",
I mean, in my case I only have one single float value for Bx1 (eg.1.3665584), and another float value for Bx2.. etc.
Should I pass what I have ( the single float value above)?
(I did pass single float values, and the program didn't crash, but it didn't give a right answer either...see part 3)
Q Part 2:
My understanding is that all four MMS SC are used to locate null points in the magnetosphere.
Then, how do I pass 4 different datasets to this function?
Should I do something like, pass data from one SC at a time, and see they all find the null(s) at the same location? Then that coordinate would be my null point.
Q Part3:
I passed some other data (than what is used in the example), but still I get the same answer as in the example.
Is this code working?
Could it be that this code is still in development phase? I guess not.. because it is a released version, right?
Thank you for reading this long post. | 17:57:38 |
| jartok | * Hi All,
Has anyone used MMS data to find null points using plasmapy.analysis.nullpoint.null_point_find?
Or may be someone has some idea how it might be done?
I have a bunch of numbers for x, y, z position (in GSM coordinates) of the MMS spacecraft (SC),and I have corresponding magnetic field values; Bx, By, Bz.
I have 4 data files, one for each SC.
Q Part 1:
As far as I can see, I only find one set of data is provided to the plasmapy.analysis.nullpoint.null_point_find function.
(Ref: https://docs.plasmapy.org/en/stable/notebooks/analysis/nullpoint.html
the second example, "Arbitrary regular grid")
It looks like there are two points P1 (5, 5, 5), and P2 (6,6,6).
So the coordinate arrays to pass to the null_point_find function is:
[x1, x2], [y1, y2], [z1, z2], that is, [5,6], [5,6], [5,6]
Then one needs to pass [Bx1, Bx2], [By1, By2], [Bz1, Bz2].
In the example, Bx1, Bx2 both are [-0.5, -0.5], [0.5, 0.5].
My question is how do I interpret this "[-0.5, -0.5], [0.5, 0.5]",
I mean, in my case I only have one single float value for Bx1 (eg.1.3665584), and another float value for Bx2.. etc.
Should I pass what I have ( the single float value above)?
(I did pass single float values, and the program did crash!!)
Q Part 2:
My understanding is that all four MMS SC are used to locate null points in the magnetosphere.
Then, how do I pass 4 different datasets to this function?
Should I do something like, pass data from one SC at a time, and see they all find the null(s) at the same location? Then that coordinate would be my null point.
Thank you for reading this long post. | 18:19:01 |
| jartok | * Hi All,
Has anyone used MMS data to find null points using plasmapy.analysis.nullpoint.null_point_find?
Or may be someone has some idea how it might be done?
I have a bunch of numbers for x, y, z position (in GSM coordinates) of the MMS spacecraft (SC),and I have corresponding magnetic field values; Bx, By, Bz.
I have 4 data files, one for each SC.
Q Part 1:
As far as I can see, I only find one set of data is provided to the plasmapy.analysis.nullpoint.null_point_find function.
(Ref: https://docs.plasmapy.org/en/stable/notebooks/analysis/nullpoint.html
the second example, "Arbitrary regular grid")
It looks like there are two points P1 (5, 5, 5), and P2 (6,6,6).
So the coordinate arrays to pass to the null_point_find function is:
[x1, x2], [y1, y2], [z1, z2], that is, [5,6], [5,6], [5,6]
Then one needs to pass [Bx1, Bx2], [By1, By2], [Bz1, Bz2].
In the example, Bx1, Bx2 both are [-0.5, -0.5], [0.5, 0.5].
My question is how do I interpret this "[-0.5, -0.5], [0.5, 0.5]",
I mean, in my case I only have one single float value for Bx1 (eg.1.3665584), and another float value for Bx2.. etc.
Q Part 2:
My understanding is that all four MMS SC are used to locate null points in the magnetosphere.
Then, how do I pass 4 different datasets to this function?
Should I do something like, pass data from one SC at a time, and see they all find the null(s) at the same location? Then that coordinate would be my null point.
Thank you for reading this long post. | 18:21:45 |
| jartok | Sorry, I had to edit. | 18:21:57 |
| jartok | Please let me explain. | 18:22:09 |
| jartok | I was running the same example code, even after changing values... so no wonder I got the same result, as in the example. | 18:22:50 |
 RamizQudsi | I will let someone who has more experience with PlasmaPy to answer that question. But Fu et. al. has a paper on how to find magnetic nulls using MMS data! | 18:22:55 |
| RamizQudsi | * I will let someone who has more experience with PlasmaPy to answer that question. But Fu et. al. has a paper on how to find magnetic nulls using MMS data! | 18:23:28 |
| RamizQudsi | Gist is, they used first order taylor expansion! | 18:24:09 |
| jartok | I read Haynes (2007), and trilinear interpolation seems to be better for non-linear fields, like the magnetic fields. | 18:24:57 |
| jartok | So I was (am) excited to "discover" that someone (PlasmaPy community) has written program using TLI. | 18:26:09 |
| jartok | * I read Haynes (2007), and trilinear interpolation (TLI) seems to be better for non-linear fields, like the magnetic fields. | 18:26:49 |
| RamizQudsi | Yeah, I agree. Fu et. al's method doesn't work as great once distance becomes larger than 0.5 d_i | 18:27:33 |
| jartok | * When I passed just one value (a float number) for each component of B, the program crashed. | 18:43:26 |
| jartok | * Hi All,
Has anyone used MMS data to find null points using plasmapy.analysis.nullpoint.null_point_find?
Or may be someone has some idea how it might be done?
I have a bunch of numbers for x, y, z position (in GSM coordinates) of the MMS spacecraft (SC),and I have corresponding magnetic field values; Bx, By, Bz.
I have 4 data files, one for each SC.
Q Part 1:
As far as I can see, I only find one set of data is provided to the plasmapy.analysis.nullpoint.null_point_find function.
(Ref: https://docs.plasmapy.org/en/stable/notebooks/analysis/nullpoint.html
the second example, "Arbitrary regular grid")
It looks like there are two points P1 (5, 5, 5), and P2 (6,6,6).
So the coordinate arrays to pass to the null_point_find function is:
[x1, x2], [y1, y2], [z1, z2], that is, [5,6], [5,6], [5,6]
Then one needs to pass [Bx1, Bx2], [By1, By2], [Bz1, Bz2].
In the example, Bx1, Bx2 both are [-0.5, -0.5], [0.5, 0.5].
My question is how do I interpret this "[-0.5, -0.5], [0.5, 0.5]",
I mean, in my case I only have one single float value for Bx1 (eg.1.3665584), and another float value for Bx2.. etc.
Q Part 2:
My understanding is that all four MMS SC are used to locate null points in the magnetosphere.
Then, how do I pass 4 different datasets to this function?
Should I do something like, pass data from one SC at a time, and see they all find the null(s) at the same location? Then that coordinate would be my null point. (edited: nope. didn't work. I got errors.)
Thank you for reading this long post. | 18:44:40 |
