Energy flows in stellar coronae
Lead Research Organisation:
University of Cambridge
Department Name: Applied Maths and Theoretical Physics
Abstract
The Sun is the only star that we can study in detail, from its interior to the outer atmosphere (corona) and the solar wind, which permeates the entire solar system. The solar corona is also an unique laboratory that we can use to understand fundamental plasma processes that occurr throughout the universe (most of which is composed of magnetised plasma). The solar irradiance and particle flux fundamentally affect space weather, our atmosphere and the global climate of our planet. Yet, we have so far failed to understand many fundamental questions about the Sun (and stars in general). The standard model of the Sun has recently been called into question. We still do not know the prime mechanisms that heat the solar corona to millions of degrees, that cause flares and eruptions, that accelerate particles, that produce the strongest emission in the Extreme Ultra Violet (EUV). We also know very little about the solar irradiance in the EUV or X-rays, and its potential effects on the global climate of our planet. As for other stars, we know that most have strong X-ray emission, however the processes that produce these X-rays are still largely unknown. This is a golden age for the physics of the solar corona, with a wealth of data gathered by recent (SOHO, TRACE, RHESSI) missions, now complemented with Hinode (Solar-B), and soon with STEREO, SDO. The two EUV spectrometers (SOHO/CDS, Hinode/EIS) have a strong UK involvement. I believe that it is timely to invest more resources into the analysis and interpretation of these spectroscopic data, because they hold the key to advance our understanding of the solar corona. The current sensitivity and resolution of EIS will allow novel studies. In particular, I intend to couple observations with theoretical modeling to understand which processes dominate the energy release and flow in the corona, by taking into account non-equilibrium and non-thermal effects in the plasma. In particular, I will study the location and evolution of heating in coronal loops in relation with the changes of the magnetic field, and energy flows during flares, in relation to chromospheric evaporation. Spectral observations and realistic atmospheric models will also shed light on the problem of why the brightest EUV lines are so bright, so in the future we will also be able to predict their emission. I also plan to use the unique 10-year long SOHO observations to characterise for the first time the EUV spectral irradiance and its variations with the solar cycle. We will then be able to study any possible effects on global climate. With the same observations I will also obtain the physical characteristics of the solar corona during the last cycle. With these and some modeling, it will be possible to simulate in detail the X-ray emission from other stars. With these simulations, and Chandra and XMM-Newton observations of stars of different ages, it will be possible to understand in which cases the observed X-ray emission could be due to the presence of a hot corona similar to an active Sun. Provision of accurate atomic data forms an integral part of this proposal, given their importance for plasma diagnostic and modeling. I plan to continue the work on the ions for the EUV and X-rays, and to provide atomic data to allow studies of non-equilibrium and non-thermal effects, which are presumably important in the solar corona.
Organisations
- University of Cambridge (Fellow, Lead Research Organisation)
- University of Orsay (Collaboration)
- HARVARD UNIVERSITY (Collaboration)
- University College London (Collaboration)
- Rutherford Appleton Laboratory (Collaboration)
- UNIVERSITY OF STRATHCLYDE (Collaboration)
- Astronomical Institute Czech Republic (Collaboration)
- UNIVERSITY OF CAMBRIDGE (Collaboration)
People |
ORCID iD |
| Giulio Del Zanna (Principal Investigator / Fellow) |
Publications
Alexander C
(2011)
Hinode observations and 3D magnetic structure of an X-ray bright point
in Astronomy & Astrophysics
Allison H
(2017)
The magnetic local time distribution of energetic electrons in the radiation belt region
in Journal of Geophysical Research: Space Physics
Andretta V
(2014)
The EUV spectrum of the Sun: SOHO CDS NIS radiances during solar cycle 23
in Astronomy & Astrophysics
Andretta V
(2012)
Coronal Diagnostics from Narrowband Images Around 30.4 nm
in Solar Physics
Badnell N
(2016)
Atomic processes for astrophysical plasmas
in Journal of Physics B: Atomic, Molecular and Optical Physics
Barstow M
(2008)
Stellar And Galactic Environment survey (SAGE)
in Experimental Astronomy
Barstow M
(2008)
Stellar and galactic environment survey (SAGE)
in Astrophysics and Space Science
Bemporad A.
(2009)
Multispacecraft observations of a prominence eruption
in ANNALES GEOPHYSICAE
Bemporad A.
(2009)
Multispacecraft observations of a prominence eruption
in ANNALES GEOPHYSICAE
BenMoussa A
(2013)
On-Orbit Degradation of Solar Instruments
in Solar Physics
Bradshaw S
(2011)
A RECONNECTION-DRIVEN RAREFACTION WAVE MODEL FOR CORONAL OUTFLOWS
in The Astrophysical Journal
Chifor C
(2008)
Magnetic flux cancellation associated with a recurring solar jet observed with Hinode , RHESSI , and STEREO /EUVI
in Astronomy & Astrophysics
Del Zanna G
(2008)
Electron-impact excitation of Be-like Mg
in Astronomy & Astrophysics
Del Zanna G
(2012)
Benchmarking atomic data for the CHIANTI atomic database: coronal lines observed by Hinode EIS
in Astronomy & Astrophysics
Del Zanna G
(2011)
A single picture for solar coronal outflows and radio noise storms
in Astronomy & Astrophysics
Del Zanna G
(2012)
Atomic data for astrophysics: Fe xii soft X-ray lines
in Astronomy & Astrophysics
Del Zanna G
(2012)
Atomic data for astrophysics: Fe x soft X-ray lines
in Astronomy & Astrophysics
Del Zanna G
(2009)
Benchmarking atomic data for astrophysics: Fe VII and other cool lines observed by Hinode EIS
in Astronomy & Astrophysics
Del Zanna G
(2010)
Atomic data from the IRON project LXVIII. Electron impact excitation of Fe xi
in Astronomy and Astrophysics
Del Zanna G
(2015)
The evolution of the emission measure distribution in the core of an active region
in Astronomy & Astrophysics
Del Zanna G
(2016)
Atomic data for astrophysics: Ni XII
in Astronomy & Astrophysics
Del Zanna G
(2015)
Benchmarking atomic data for astrophysics: Si iii
in Astronomy & Astrophysics
Del Zanna G
(2016)
Atomic data and density diagnostics for S iv
in Monthly Notices of the Royal Astronomical Society
Del Zanna G
(2015)
The EUV spectrum of the Sun: Irradiances during 1998-2014
in Astronomy & Astrophysics
Del Zanna G
(2014)
Elemental abundances and temperatures of quiescent solar active region cores from X-ray observations
in Astronomy & Astrophysics
Del Zanna G
(2012)
Atomic data for astrophysics: Fe xi soft X-ray lines
in Astronomy & Astrophysics
Del Zanna G
(2013)
The multi-thermal emission in solar active regions
in Astronomy & Astrophysics
Del Zanna G
(2015)
The EUV spectrum of the Sun: SOHO, SEM, and CDS irradiances
in Astronomy & Astrophysics
Del Zanna G
(2014)
Atomic data for astrophysics: Fe IX
in Astronomy & Astrophysics
Del Zanna G
(2010)
The 22 May 2007 B-class flare: new insights from Hinode observations
in Astronomy & Astrophysics
Del Zanna G
(2011)
The EUV spectrum of the Sun: SOHO CDS NIS irradiances from 1998 until 2010
in Astronomy & Astrophysics
Del Zanna G
(2010)
The EUV spectrum of the Sun: long-term variations in the SOHO CDS NIS spectral responsivities
in Astronomy and Astrophysics
Del Zanna G
(2009)
Benchmarking atomic data for astrophysics: Fe XVII EUV lines
in Astronomy & Astrophysics
Del Zanna G
(2015)
On the validity of the ICFT R-matrix method: Fe xiv
in Monthly Notices of the Royal Astronomical Society
Del Zanna G
(2012)
Benchmarking atomic data for astrophysics: a first look at the soft X-ray lines
in Astronomy & Astrophysics
Del Zanna G
(2014)
Atomic data for astrophysics: improved collision strengths for Fe viii
in Astronomy & Astrophysics
Del Zanna G
(2015)
CHIANTI - An atomic database for emission lines. Version 8
in Astronomy & Astrophysics
Del Zanna G
(2011)
Benchmarking atomic data for astrophysics: Fe xiii EUV lines
in Astronomy & Astrophysics
Del Zanna G
(2011)
SDO AIA and Hinode EIS observations of "warm" loops
in Astronomy & Astrophysics
Del Zanna G
(2012)
Atomic data for astrophysics: Fe xiii soft X-ray lines
in Astronomy & Astrophysics
Del Zanna G
(2014)
Atomic data for astrophysics: Ni XV
in Astronomy & Astrophysics
Del Zanna G
(2013)
Spectral diagnostics with the SDO EVE flare lines
in Astronomy & Astrophysics
Del Zanna G
(2018)
Solar Coronal Lines in the Visible and Infrared: A Rough Guide
in The Astrophysical Journal
Del Zanna G
(2011)
Benchmarking atomic data for astrophysics: Fe XVII X-ray lines
in Astronomy & Astrophysics
Del Zanna G
(2008)
Flare lines in Hinode EIS spectra
in Astronomy & Astrophysics
Del Zanna G
(2009)
Benchmarking atomic data for astrophysics: Fe VIII EUV lines
in Astronomy & Astrophysics
Del Zanna G
(2013)
A revised radiometric calibration for the Hinode/EIS instrument
in Astronomy & Astrophysics
Del Zanna G
(2014)
Atomic data for astrophysics: Ni XI
in Astronomy & Astrophysics
Del Zanna G
(2010)
Benchmarking atomic data for astrophysics: Fe xi
in Astronomy and Astrophysics
Del Zanna G
(2008)
Flows in active region loops observed by Hinode EIS
in Astronomy & Astrophysics
| Description | My long-term project has managed to achieve, thanks to many different grants, the original goal of producing accurate solar radiances and irradiances in the extreme ultraviolet. For the first time, we have these measurements along a full solar cycle, from 1998 to 2014. So we are now able to quantify the solar changes of the EUV irradiance, and where these changes are originating. I have also developed a better understanding of the solar spectrum by calculating and benchmarking new atomic data. |
| Exploitation Route | The EUV irradiances are part of the EU FP7 SOLID framework, which has produced observed and modelled spectral irradiances of the Sun. The SOLID results are used to improve global circulation models of the climate which in turn provide an input to the IPCC reports. The atomic data are widely used. As part of the work, I produced a radiometric calibration for the SOHO CDS instrument, for its entire lifetime. The PI institute is currently providing calibrated data for the entire mission using my calibration. |
| Sectors | Aerospace, Defence and Marine,Education,Environment |
| Description | The EUV irradiances are part of the EU FP7 SOLID framework, which has produced observed and modelled spectral irradiances of the Sun. The SOLID results are used to improve global circulation models of the climate which in turn provide an input to the IPCC reports. The atomic data that I have calculated and benchmarked have a wide distribution and are used not just within astrophysics, but also by fusion research via the ADAS consortium, the main diagnostic modelling package found at all major fusion laboratories in the world (including the European JET and ITER). The CHIANTI atomic data have been made available to VAMDC (www.vamdc.eu), a large European consortium of providers of atomic and molecular data. VAMDC data are used by a very wide community, including industries that are researching and developing new lighting sources. |
| First Year Of Impact | 2015 |
| Sector | Education,Environment,Other |
| Impact Types | Societal |
| Description | Consolidated bridging grant |
| Amount | £120,000 (GBP) |
| Funding ID | ST/J001570/1, PI: Gordon Ogilvie |
| Organisation | Science and Technologies Facilities Council (STFC) |
| Sector | Public |
| Country | United Kingdom |
| Start | 10/2012 |
| End | 03/2015 |
| Description | Consolidated grant |
| Amount | £100,000 (GBP) |
| Organisation | Science and Technologies Facilities Council (STFC) |
| Sector | Public |
| Country | United Kingdom |
| Start | 04/2014 |
| End | 03/2017 |
| Description | SOLID FP7 network |
| Amount | € 75,000 (EUR) |
| Funding ID | EC FP7 CP 313188 |
| Organisation | European Commission |
| Sector | Public |
| Country | European Union (EU) |
| Start | 12/2012 |
| End | 11/2015 |
| Title | CHIANTI |
| Description | CHIANTI is the reference atomic database for ions for use in astrophysics. The last update was in 2015 and it has been used to model solar irradiances, among other applications. CHIANTI is widely used within VAMDC, an EU infrastructure for atomic and molecular data. |
| Type Of Material | Database/Collection of data |
| Provided To Others? | Yes |
| Impact | A few thousands of citations. |
| URL | http://www.chiantidatabase.org |
| Title | CHIANTI database v.8 |
| Description | The culmination of nearly 6 years of work was the v.8 CHIANTI database, where the models for the solar spectral lines important for irradiance were updated. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2015 |
| Provided To Others? | Yes |
| Impact | The database is used world-wide, has about 3000 direct citations, and about 300 indirect ones /year. |
| URL | http://chiantidatabase.org |
| Title | EUV solar irradiance |
| Description | I have produced within SOLID a database of solar EUV irradiances during 1998-2014. They are being used to benchmark modelling, which in turn will be used as solar forcing by climate modellers. |
| Type Of Material | Database/Collection of data |
| Provided To Others? | No |
| Impact | Not yet. Work is in progress. |
| Description | APAP-Network Ref: PP/E001254/1 |
| Organisation | University of Strathclyde |
| Department | Department of Physics |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | I have done atomic physics calculations, have benchmarked them against experimental data, and used them for the analysis of spectra from stellar coronae. I have also distributed the atomic data within CHIANTI and VAMDC (an EU FP7 network). |
| Collaborator Contribution | Prof. N.R.Badnell (PI of the grant,University of Strathclyde) has developed and mantained the codes used for atomic physics calculations, and I have collaborated with him on various projects. |
| Impact | In the Jan 2006 - Dec 2010 timeframe the APAP team published 101 refereed papers. They are all highest-quality papers, describing atomic data which are used world-wide by almost all atomic databases and modelling codes, and are directly or indirectly cited by hundreds of refereed papers per year. |
| Start Year | 2008 |
| Description | Associated scientist with CfA on various missions/proposals |
| Organisation | Harvard University |
| Department | Harvard-Smithsonian Center for Astrophysics |
| Country | United States |
| Sector | Academic/University |
| PI Contribution | Contribute to various proposals for space missions (COSIE, MAGIXS), to the analysis of current missions (IRIS). Also contributed to AIRSPEC, an new infrared spectrometer, and DKIST, a ground-based solar telescope. |
| Collaborator Contribution | Provide access to data and resources. |
| Impact | Various research papers. |
| Start Year | 2010 |
| Description | Co-I of Solar Orbiter instruments |
| Organisation | Rutherford Appleton Laboratory |
| Department | RAL Space |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | I am co-I of the Solar Orbiter SPICE and EUI. I am . associated scientist of the SOlar Orbiter METIS instrument. I am contributing in refining the best science, calibration and operating modes. |
| Collaborator Contribution | Building instruments, calibration, on-board software |
| Impact | Most of the outcomes will come in the future. A few papers are in progress. |
| Start Year | 2010 |
| Description | Co-I of Solar Orbiter instruments |
| Organisation | University College London |
| Department | Department of Space and Climate Physics (MSSL) |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | I am co-I of the Solar Orbiter SPICE and EUI. I am . associated scientist of the SOlar Orbiter METIS instrument. I am contributing in refining the best science, calibration and operating modes. |
| Collaborator Contribution | Building instruments, calibration, on-board software |
| Impact | Most of the outcomes will come in the future. A few papers are in progress. |
| Start Year | 2010 |
| Description | DAMTP RG |
| Organisation | University of Cambridge |
| Department | Department of Applied Mathematics and Theoretical Physics (DAMTP) |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | I have collaborated on various activites, student supervision, seminars, outreach, other than research. |
| Collaborator Contribution | We have collaborated on many projects as the publications clearly show. |
| Impact | See publication list. |
| Start Year | 2008 |
| Description | ISSI team meeting (2018-2019) on solar abundances - Solar Orbiter |
| Organisation | University of Orsay |
| Department | Space Astrophysics Institute |
| Country | France |
| Sector | Academic/University |
| PI Contribution | This is an international collaboration with several researchers/institutes, to study how to link in-situ with remote-sensing observations with Solar Orbiter. I contributed in terms of atomic data, diagnostics, and a specific project on active regions. |
| Collaborator Contribution | Each partner will contribute on the basis of their expertise. |
| Impact | The collaboration only started. |
| Start Year | 2018 |
| Description | ISSI team meeting on non-equilibrium plasma |
| Organisation | Astronomical Institute Czech Republic |
| Country | Czech Republic |
| Sector | Academic/University |
| PI Contribution | This is an international collaboration among experts on diagnostics of non-equilibrium plasma. Del Zanna and Mason contributed in terms of atomic data and diagnostics, and wrote part of a long review. |
| Collaborator Contribution | Each partner contributed to the review. |
| Impact | Dudik et al., Sol. Phys., 2017. DOI: 10.1007/s11207-017-1125-0 |
| Start Year | 2012 |
| Description | Invited lectures |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | Yes |
| Geographic Reach | Local |
| Primary Audience | Schools |
| Results and Impact | This was a very large audience keen to learn about the recent research on the solar atmosphere. I received many questions and congratulations from the audience. I have also given lectures at schools to children on a few occasions (the last one in 2015 was the solar eclipse) N/A |
| Year(s) Of Engagement Activity | 2011,2014,2015 |
| Description | Open Day |
| Form Of Engagement Activity | Participation in an open day or visit at my research institution |
| Part Of Official Scheme? | Yes |
| Geographic Reach | Local |
| Primary Audience | Public/other audiences |
| Results and Impact | This event is targeted to children, and is regularly visited by hundreds of people during one day. Many children become very enthusiastic about studying physcis and astronomy. These events can affect some of them for life. |
| Year(s) Of Engagement Activity | 2009,2011,2012,2014 |