Dear Loops friends,
You might be interested in a paper that Manuel Luna and I recently submitted on "The Role of Asymmetries in Thermal Non-Equilibrium." It can be downloaded at https://urldefense.proofpoint.com/v2/url?u=http-3A__arxiv.org_abs_1905.0976…
I look forward to discussing any questions or comments you may have at the Loops Workshop in a couple weeks.
Thanks,
Jim
ABSTRACT
Thermal non-equilibrium (TNE) is a fascinating situation that occurs in coronal magnetic flux tubes (loops) for which no solution to the steady-state fluid equations exists. The plasma is constantly evolving even though the heating that produces the hot temperatures does not. This is the likely explanation of isolated phenomena such as prominences, coronal rain, and long-period pulsating loops, but it may also have much broader relevance. As known for some time, TNE requires that the heating be both (quasi) steady and concentrated at low coronal altitudes. Recent studies indicate that asymmetries are also important, with large enough asymmetries in the heating and/or cross-sectional area resulting in steady flow rather than TNE. Using reasonable approximations, we have derived two formulae for quantifying the conditions necessary for TNE. As a rough rule of thumb, the ratio of apex to footpoint heating must be less than about 0.1, and asymmetries must be less than about a factor of 3. The precise values are case dependent. We have tested our formulae with 1D hydrodynamic loop simulations and find a very acceptable agreement. These results are important for developing physical insight about TNE and assessing how widespread it may be on the Sun.
********************************************************************************
James A. Klimchuk
NASA Goddard Space Flight Center
Solar Physics Lab, Code 671
Bldg. 21, Rm. 158
Greenbelt, MD 20771
USA
Phone: 1-301-286-9060
Fax: 1-301-286-7194
E-mail: James.A.Klimchuk(a)nasa.gov<mailto:James.A.Klimchuk@nasa.gov>
Homepage: http://science.gsfc.nasa.gov/sed/bio/james.a.klimchuk<http://science.gsfc.nasa.gov/sed/index.cfm?fuseAction=people.jumpBio&&iPhon…>
No endorsement by NASA is implied for any correspondence related to my official role in professional organizations.
********************************************************************************
Dear all,
I wanted to make you aware of an excellent resource that is currently being compiled by Monica Bobra and James Mason: the HelioML e-book (https://helioml.github.io/HelioML/chapters/title).
We have recently contributed a chapter based on DeepEM: a (supervised) deep learning approach to DEM inversion. DeepEM is currently under development on Github (https://github.com/PaulJWright/DeepEM), and DeepEM has been designed to both accelerate the computation of DEM solutions, and reduce erroneous solutions provided by pre-existing inversion methods. The underlying idea is that a neural network should be able to learn a generalized mapping in order to transform an SDO/AIA input vector (6x1x1) to the DEM output vector (Nx1x1, where N is the number of temperature bins of the DEM solution) also retain the fidelity to the original inversion method.
In our DeepEM chapter we provide a simple model in order to demonstrate how easy it is to apply deep learning techniques to your own research. This very simple implementation is trained on one set of 512x512 AIA images, and corresponding Basis Pursuit DEM solutions. This implementation returns >10 Million DEM/s with similar fidelity to Basis Pursuit. A gif of how this implementation compares to Basis Pursuit is shown here: https://twitter.com/PaulJWright/status/1068115587614863360<https://twitter.com/PaulJWright/status/1068115587614863360,>, and I hope that this chapter, and e-book in general, will encourage those who are interested to applying deep learning to their research.
Cheers,
Paul
---
Paul J. Wright
Research Assistant & Ph.D. Student
Astronomy & Astrophysics Group
SUPA School of Physics & Astronomy
Kelvin Building
University of Glasgow
Glasgow, UK
G12 8QQ
Web: http://www.pauljwright.co.uk
Email: paul.wright(a)glasgow.ac.uk<mailto:paul.wright@glasgow.ac.uk>
Email (permanent): paul(a)pauljwright.co.uk
<mailto:paul@pauljwright.co.uk>
Dear All,
Following on from our recent announcement that the ninth Coronal Loops
Workshop will be held in 2019 at the University of St. Andrews, Scotland, I
can confirm that the Workshop will run for 3.5 days from Tuesday 11th to
Friday 14th June. Put the date in your diaries!
Best wishes,
Steve Bradshaw
(on behalf of the Coronal Loops Workshops Steering Committee)
Dr. Stephen J. Bradshaw
(Associate Professor of Physics and Astronomy / Chair of the Undergraduate
Program in Physics and Astronomy)
Department of Physics and Astronomy (MS 108)
Rice University,
6100 Main Street,
Houston,
TX 77005,
USA.
Tel: +1 713 348 4045
Email: <mailto:stephen.bradshaw@rice.edu> stephen.bradshaw(a)rice.edu
Web: solar.rice.edu
Hi Loopy folks,
just to let you know that our massive Solar Physics Living Review has now
been released on astro-ph:
Solar UV and X-Ray Spectral Diagnostics
Giulio Del Zanna, Helen E. Mason
https://arxiv.org/abs/1809.01618
Helen
--
Dear Colleagues,
I am very happy to announce that the ninth Coronal Loops Workshop, to be
held in 2019, will be hosted by the Solar and Magnetospheric Theory Group at
the University of St. Andrews, Scotland. Professor Ineke De Moortel will
Chair the SOC and LOC.
We are currently in the process of determining the dates for the Workshop
and a follow-up announcement containing this information for your diaries
will be made shortly.
With best wishes,
Steve Bradshaw
(on behalf of the Coronal Loops Workshops Steering Committee)
Dr. Stephen J. Bradshaw
(Associate Professor of Physics and Astronomy)
Department of Physics and Astronomy (MS 108)
Rice University,
6100 Main Street,
Houston,
TX 77005,
USA.
Tel: +1 713 348 4045
Email: <mailto:stephen.bradshaw@rice.edu> stephen.bradshaw(a)rice.edu
Web: solar.rice.edu
Hello everyone,
I just wanted to send a brief reminder re. the call for proposals to host
the 9th Coronal Loops Workshop. Due date: July 27th. Other details below.
Best wishes,
Steve
From: Loops <loops-bounces(a)solar.physics.montana.edu> On Behalf Of Stephen
Bradshaw
Sent: Monday, June 18, 2018 2:18 PM
To: loops(a)solar.physics.montana.edu
Subject: [Loops] Call for Proposals to Host the 9th Coronal Loops Workshop
in 2019
Dear Colleagues,
The Coronal Loops Workshop series, inaugurated in Paris (2002), has been
tremendously successful in bringing together researchers from all over the
world to discuss current problems related to the physics of closed magnetic
structures in the solar corona, and to present their progress toward solving
them. The Workshops have also provided an excellent forum for young
researchers to participate in discussions and to showcase their work. The
previous Workshop in the series (Loops VIII) was held in Palermo, in June
2017 (http://www.astropa.unipa.it/CLW2017/CLW2017.html).
The Steering Committee for the Coronal Loops Workshops now invites proposals
to host the 9th Workshop in the series (Loops IX), which will be convened in
2019.
Letters of Intent to submit a proposal are optional, but would be useful to
the Steering Committee if sent no later than July 13th. Full proposals must
be submitted on or before July 27th.
Proposals should be no more than 3 pages in length and must include:
* A description of the proposed location (including accessibility from
major transport hubs).
* The preferred dates, avoiding conflicts with other major community
meetings in 2019.
(e.g. EGU [Apr. 7 - 12]; IAU Cambridge [Apr. 14 - 19]; CESPM [May. 6 - 10];
NAM/UKSP [Jun. 30 - Jul. 4]; IAUS 354 [Jun. 30 - Jul. 6]; AOGS [Jul. 28 -
Aug. 2]; Hinode 13 [Sept. 2 - 6])
* A description of the venue, meeting room, and facilities.
* An overview of the local accommodation and dining options.
* Transport between the accommodation and the workshop venue (e.g. a
walk, bus ride, etc).
* An estimate of the total cost of the workshop.
* An estimate of the registration fee (assuming 60 participants).
* Who will Chair the SOC/LOC?
* Any other comments that you think would be helpful to the Steering
Committee in support of your proposal.
Please send letters of intent, full proposals, and requests for a copy of
the Workshop Guidelines, to Steve Bradshaw (Steering Committee Chair:
stephen.bradshaw(a)rice.edu <mailto:stephen.bradshaw@rice.edu> ).
With best wishes,
Steve Bradshaw
(on behalf of the Coronal Loops Workshops Steering Committee)
Dr. Stephen J. Bradshaw
(Associate Professor of Physics and Astronomy)
Department of Physics and Astronomy (MS 108)
Rice University,
6100 Main Street,
Houston,
TX 77005,
USA.
Tel: +1 713 348 4045
Email: <mailto:stephen.bradshaw@rice.edu> stephen.bradshaw(a)rice.edu
Web: solar.rice.edu
Dear Colleagues,
The Coronal Loops Workshop series, inaugurated in Paris (2002), has been
tremendously successful in bringing together researchers from all over the
world to discuss current problems related to the physics of closed magnetic
structures in the solar corona, and to present their progress toward solving
them. The Workshops have also provided an excellent forum for young
researchers to participate in discussions and to showcase their work. The
previous Workshop in the series (Loops VIII) was held in Palermo, in June
2017 (http://www.astropa.unipa.it/CLW2017/CLW2017.html).
The Steering Committee for the Coronal Loops Workshops now invites proposals
to host the 9th Workshop in the series (Loops IX), which will be convened in
2019.
Letters of Intent to submit a proposal are optional, but would be useful to
the Steering Committee if sent no later than July 13th. Full proposals must
be submitted on or before July 27th.
Proposals should be no more than 3 pages in length and must include:
* A description of the proposed location (including accessibility from
major transport hubs).
* The preferred dates, avoiding conflicts with other major community
meetings in 2019.
(e.g. EGU [Apr. 7 - 12]; IAU Cambridge [Apr. 14 - 19]; CESPM [May. 6 - 10];
NAM/UKSP [Jun. 30 - Jul. 4]; IAUS 354 [Jun. 30 - Jul. 6]; AOGS [Jul. 28 -
Aug. 2]; Hinode 13 [Sept. 2 - 6])
* A description of the venue, meeting room, and facilities.
* An overview of the local accommodation and dining options.
* Transport between the accommodation and the workshop venue (e.g. a
walk, bus ride, etc).
* An estimate of the total cost of the workshop.
* An estimate of the registration fee (assuming 60 participants).
* Who will Chair the SOC/LOC?
* Any other comments that you think would be helpful to the Steering
Committee in support of your proposal.
Please send letters of intent, full proposals, and requests for a copy of
the Workshop Guidelines, to Steve Bradshaw (Steering Committee Chair:
stephen.bradshaw(a)rice.edu <mailto:stephen.bradshaw@rice.edu> ).
With best wishes,
Steve Bradshaw
(on behalf of the Coronal Loops Workshops Steering Committee)
Dr. Stephen J. Bradshaw
(Associate Professor of Physics and Astronomy)
Department of Physics and Astronomy (MS 108)
Rice University,
6100 Main Street,
Houston,
TX 77005,
USA.
Tel: +1 713 348 4045
Email: <mailto:stephen.bradshaw@rice.edu> stephen.bradshaw(a)rice.edu
Web: solar.rice.edu
Dear Colleagues,
Following the recent call for nominations to the Steering Committee for the
Coronal Loops Workshops, and the election held by the current membership of
the Steering Committee (SC), I am very pleased to announce that:
David Brooks
Fabio Reale
Durgesh Tripathi
have been elected to each serve a six year term on the SC. Congratulations
to them and thank you to everyone who participated in the nominating
process!
I would also like to take this opportunity to thank once again Susanna,
Inaki, and Nicki for their long service to the Workshop Series.
Now that our new SC is in place, a call for proposals to host the next
Workshop (to be held sometime during 2019) will be released soon.
Best wishes,
Steve Bradshaw
(on behalf of the Coronal Loops Workshops Steering Committee)
From: Stephen Bradshaw <stephen.bradshaw(a)rice.edu>
Sent: Monday, April 16, 2018 10:56 AM
To: 'loops(a)solar.physics.montana.edu' <loops(a)solar.physics.montana.edu>
Subject: Call for Nominations to the Coronal Loops Workshops Steering
Committee
Dear Colleagues,
The Coronal Loops Workshop series, inaugurated in Paris (2002) with the most
recent Workshop in Palermo (2017), has been tremendously successful in
bringing together researchers from all over the world to discuss current
problems related to the physics of closed magnetic structures in the solar
corona, and to present their progress toward solving them. The Workshops
have also provided an excellent venue for young researchers to participate
in discussions and to showcase their work.
The Steering Committee for the Coronal Loops Workshops is responsible for
soliciting and selecting Workshop proposals, and assisting / advising each
Scientific Organizing Committee in choosing a topical, over-arching theme
and setting an agenda and goals for their Workshop.
The current members of the Steering Committee are: Steve Bradshaw [Chair];
Philippa Browning; Ineke De Moortel; Giulio Del Zanna; Viggo Hansteen;
Susanna Parenti; Paola Testa; Ignacio Ugarte-Urra; Nicholeen Viall.
Three members of the Steering Committee (Susanna Parenti, Ignacio
Ugarte-Urra, and Nicholeen Viall) have reached the end of their 6 year
terms. Since they were elected in 2012 they have been involved in the
organization of 3 Loops Workshops (Loops VI - VIII, not forgetting that
Inaki also Chaired Loops V) and the Loops community owes them a great deal
of thanks and appreciation for their tremendously hard work on our behalf.
It is now time to elect 3 new members of the Steering Committee. We are
soliciting nominations and self-nominations, the latter are particularly
encouraged, to help ensure a diverse pool of candidates to represent the
interests of our community, for scientists who are active in the broad field
of the physics of closed magnetic structures in the solar corona, to serve
on the Coronal Loops Workshops Steering Committee for a 6 year term.
Please submit your nominations and self-nominations to Steve Bradshaw
(Steering Committee Chair: <mailto:stephen.bradshaw@rice.edu>
stephen.bradshaw(a)rice.edu) no later than Monday April 30th. The current
members of the Steering Committee will vote per the Bylaws and the
newly-elected members will be duly contacted and announced directly
thereafter.
With best wishes,
Steve Bradshaw
(on behalf of the Coronal Loops Workshops Steering Committee)
Dr. Stephen J. Bradshaw
(Associate Professor of Physics and Astronomy)
Department of Physics and Astronomy (MS 108)
Rice University,
6100 Main Street,
Houston,
TX 77005,
USA.
Tel: +1 713 348 4045
Email: <mailto:stephen.bradshaw@rice.edu> stephen.bradshaw(a)rice.edu
Web: solar.rice.edu
Dear Colleagues,
The Coronal Loops Workshop series, inaugurated in Paris (2002) with the most
recent Workshop in Palermo (2017), has been tremendously successful in
bringing together researchers from all over the world to discuss current
problems related to the physics of closed magnetic structures in the solar
corona, and to present their progress toward solving them. The Workshops
have also provided an excellent venue for young researchers to participate
in discussions and to showcase their work.
The Steering Committee for the Coronal Loops Workshops is responsible for
soliciting and selecting Workshop proposals, and assisting / advising each
Scientific Organizing Committee in choosing a topical, over-arching theme
and setting an agenda and goals for their Workshop.
The current members of the Steering Committee are: Steve Bradshaw [Chair];
Philippa Browning; Ineke De Moortel; Giulio Del Zanna; Viggo Hansteen;
Susanna Parenti; Paola Testa; Ignacio Ugarte-Urra; Nicholeen Viall.
Three members of the Steering Committee (Susanna Parenti, Ignacio
Ugarte-Urra, and Nicholeen Viall) have reached the end of their 6 year
terms. Since they were elected in 2012 they have been involved in the
organization of 3 Loops Workshops (Loops VI - VIII, not forgetting that
Inaki also Chaired Loops V) and the Loops community owes them a great deal
of thanks and appreciation for their tremendously hard work on our behalf.
It is now time to elect 3 new members of the Steering Committee. We are
soliciting nominations and self-nominations, the latter are particularly
encouraged, to help ensure a diverse pool of candidates to represent the
interests of our community, for scientists who are active in the broad field
of the physics of closed magnetic structures in the solar corona, to serve
on the Coronal Loops Workshops Steering Committee for a 6 year term.
Please submit your nominations and self-nominations to Steve Bradshaw
(Steering Committee Chair: <mailto:stephen.bradshaw@rice.edu>
stephen.bradshaw(a)rice.edu) no later than Monday April 30th. The current
members of the Steering Committee will vote per the Bylaws and the
newly-elected members will be duly contacted and announced directly
thereafter.
With best wishes,
Steve Bradshaw
(on behalf of the Coronal Loops Workshops Steering Committee)
Dr. Stephen J. Bradshaw
(Associate Professor of Physics and Astronomy)
Department of Physics and Astronomy (MS 108)
Rice University,
6100 Main Street,
Houston,
TX 77005,
USA.
Tel: +1 713 348 4045
Email: <mailto:stephen.bradshaw@rice.edu> stephen.bradshaw(a)rice.edu
Web: solar.rice.edu