ELI NP hosts the most powerful laser in the world with a power of 10 PW. The ELI project itself was initiated by Nobel Laureate Gérard Mourou and funded by the host nations as well as the European Regional Development Fund. Magurele is located on the outskirts of Bucharest, the capital of the Central European state of Romania. A city where new office towers alternate with old residential buildings. And where the palace of the dictator Nicolae Ceaușescu is still enthroned above the center. Once the second biggest governmental building in the world, it hosts the Romanian parliament today.
Trouble in paradise
ELI NP has had some bad press recently, namely a news article from the science magazine nature. It was quite critical of the institute’s management, quoting heavy allegations from IFIN HH employees against former IFIN director Nicolae V. Zamfir, who is now project director for ELI NP. Employees of the laser institute, in turn, published an open letter supporting Zamfir.
If that conflict wouldn’t be enough, ELI NP was shaken by a problem that raised attention in Brussels: A variable energy gamma-ray beam system, the second major device beside the two 10 PW lasers, was delayed in delivery and Zamfir moved the contract to another supplier. This move was brought to court. And it led to a delay in project procurement. New delivery date for the gamma system is 2023. While the laser system is on plan, the delay with the gamma source is not, and thus, Romania is not included in the application to build a European Research Infrastructure Consortium ERIC. The whole discussion is now elevated to a governmental level.
The new ERIC will be crucial for the future financing of the common infrastructure. Allen Weeks, Director General of this organization, told me “After a decade of planning and construction, the newly formed ELI ERIC will organize the joint scientific user program and begin to coordinate the technical operation.”
So far ELI ERIC includes representatives of the Czech and the Hungarian government (host nations for the ELI branches ELI BL and ELI ALPS) along with Italy and Lithuania. Germany and the United Kingdom are founding observers.
“Romania with ELI NP should become part of ERIC, of course,” added Weeks. "There is an ongoing political discussion about how Romania can become an ERIC member and in parallel the ELI-NP facility is together in the EUR 20Million European project IMPULSE with the other facilities to determine how to best cooperate on the scientific operations."
Running the most powerful laser of the world
When I read the nature news about a month ago I was wondering what people do there and what the status of the laser is. Thus, I contacted Ioan Dancus, head of the Laser Systems Department at ELI NP. He invited me to visit the facility. And he drove me through the lively traffic of the Romanian capital. Ioan is a laser physicist who remained there, even when a scientist’s salary was down to 50 USD per month. This has changed for quite some time already. The payment is fair now and other Romanians return home, joined by international scientists.
Ioan has responsibility for one of the most exciting laser systems in the world now. “In August we tested the whole system, just the final parabolas were replaced by a beam dump. And we reached 10 Petawatt with one shot per minute.” That is currently the highest laser power in the world.
The High Power Laser System HPLS at ELI NP has two huge arms with three main amplifier stages. Each stage can be used as beamline with chirp-compensated outlet for powers of 100 TW, 1 PW and 10 PW, respectively. The pulse duration is about 22 fs. The system has been built by the French company Thales, which also signed a 40 month warranty starting on January 1, 2020.
When Ioan showed me the NASA-style control room of the HPLS, the team was doing experiments with the 100 TW beam, i.e. with the front end and the first amplifier chain running. The whole system is based on TiSa-crystals, pumped by batteries of green lasers. It runs at 10 Hz. For the subsequent amplifier chains, the frequency is reduced to 1 Hz (1 PW) or to one shot per minute (10 PW).
In August 2020, the systems had been tested to deliver their nominal power throughout the entire amplifier and the 10 PW compressor in one arm. The missing off-axis parabolas will be delivered in November 2020 (1 PW) and mid 2021 (10 PW), enabling a series of commissioning experiments with all amplifier stages. Such commissioning experiments have been selected from a number of international submissions and the respective colleagues from abroad will participate in this next stage of tests.
Exciting science ahead
Once the parabolas are introduced, they will enable exciting and entirely new science. Such as measuring intensities beyond 1022 W/cm², which nobody has done before. Kazuo Tanaka, Scientific Director of ELI NP, gave me an introduction to this fascinating scientific challenge.
Kazuo is a well-known expert for laser fusion research. After retiring from his professorship at Osaka University he took a new job on the other side of the world at ELI NP. “It is a chance to build up something new. Here we open new horizons for laser nuclear physics,” he is enthusiastic about his new appointment.
As a laser physicist deeply immersed in the field of high-power laser systems, I find the developments at ELI NP particularly intriguing. The Extreme Light Infrastructure (ELI) project, initiated by Nobel Laureate Gérard Mourou, has established itself as a groundbreaking endeavor, hosting the most powerful laser in the world with an astounding power of 10 Petawatts (PW).
One aspect of ELI NP that caught my attention is its recent mention in a science magazine, Nature. The article highlighted some controversies and challenges faced by the institute, including management issues and a delay in the delivery of a variable energy gamma-ray beam system, a significant component alongside the two 10 PW lasers. This setback led to a legal dispute and a subsequent delay in project procurement, with a new delivery date for the gamma system set for 2023.
The political implications of these challenges are noteworthy, as Romania's inclusion in the European Research Infrastructure Consortium (ERIC) is at stake. ELI ERIC, formed after a decade of planning and construction, is crucial for coordinating the technical operation and organizing the joint scientific user program. Currently, ELI ERIC includes representatives from the Czech and Hungarian governments, Italy, and Lithuania, with Germany and the United Kingdom as founding observers.
The focal point of ELI NP is the High Power Laser System (HPLS), a remarkable feat built by the French company Thales. The HPLS boasts two massive arms with three main amplifier stages each, capable of delivering powers of 100 TW, 1 PW, and the record-breaking 10 PW. The pulse duration is approximately 22 femtoseconds, and the system operates at different frequencies for various amplifier chains.
I had the privilege of conversing with Ioan Dancus, the head of the Laser Systems Department at ELI NP. He shared insights into the HPLS's capabilities, revealing that in August, the system achieved 10 PW with one shot per minute, marking it as the highest laser power in the world. The control room, resembling a NASA-style operation center, showcased ongoing experiments with the 100 TW beam.
What's truly exciting about ELI NP's capabilities is the upcoming introduction of off-axis parabolas, scheduled for November 2020 (1 PW) and mid-2021 (10 PW). These parabolas will enable groundbreaking experiments, such as measuring intensities beyond 10^22 W/cm²—a scientific endeavor that has never been undertaken before.
In my exploration of ELI NP, I also had the opportunity to learn from Kazuo Tanaka, the Scientific Director of ELI NP, a renowned expert in laser fusion research. His enthusiasm for the project stems from the chance to open new horizons for laser nuclear physics, ushering in a phase of exciting and pioneering scientific challenges. With ELI NP at the forefront of laser technology, the future holds promise for groundbreaking advancements in the field.
