Showing posts with label France. Show all posts
Showing posts with label France. Show all posts

Monday, May 25, 2015

France's adjusted Military Planning Law



France has changed course on military reductions, cancelling a good share of the planned reduction in the number of personnel and making a sizeable adjustement to funding, which has brought about an update to the plans, which include a major restructuring of the Army, under project Au Contact!, "in contact". 

The main items in the reworked plans include: 

- Army's operational, deployable manpower at 77.000 (versus 66.000 target with the earlier cuts)
- 1000 more men to the Special Forces with the creation of the GAOS, Groupement d'Appui Auix Operations Speciales; a support battalion not unlike 1 PARA SFSG in the UK 
- 1000 men to the Intelligence and ISTAR forces
- 1000 men to cybersecurity 

The Army's new structure will be detailed on May 28, but we know that the restructuring will deliver 6 land manoeuvre brigades (a cut of one HQ, the current 3rd brigade), of which two will be heavy armoured, two medium, wheeled and equipped with the new VBMR 6x6 vehicles and EBRC 6x6 reconnaissance vehicle, one Parachute and one Mountain. These brigades will have some 7000 men each, with up to 7 regiments. Two deployable Division HQs will command the brigades, three each. 
One Aviation Brigade is to be formed to bring all helicopter regiments under a unified command. This airmobile brigade will not have organic ground units, it seems, but will provide airmobility to the infantry of the line brigades. 

The Navy says that a 7th Commando unit will be raised. Its unit name hasn't yet been selected. 

 
A first graphic showing the reorganization of the army commands. More details should become available on May 28.


Several important items of equipment have been added: 

- 7 Tiger attack helicopters, bringing total planned purchase up from 60 to 67. The procurement of a laser-guided rocket to complement Hellfire missiles is planned. Hellfire itself will be replaced in 2021, most likely with an air launched development of the new MMP anti-tank missile in development for the Army, would be my guess.
The Tiger will continue to be complemented by around 80 armed Gazelle helicopters. The aim is keeping attack and reconnaissance helicopters at 146 in total.

Replacement for the elderly Gazelle should come under project HIL (hélicoptère interarmées léger) in the 2020s. The HIL should replace Army Gazelle and Air Force Fennec, and Navy Dauphin and Alouette III. The programme used to be earlier known as HC4 - Hélicoptère Classe 4 Tonnes.


- 6 more NH-90 TTH battlefield utility helicopters, bringing planned purchases to 74. These will complement 8 Caracal in use by the Special Forces, plus 26 Cougar and a number of Pumas. The total of utility helicopters in the long-term is set at 115, and more NH-90s are planned to be purchased later to keep the total unchanged as the Puma is phased out. The reductions will be progressive: in 2020 there will still be more than 115 helicopters, considering all types.

- A 3rd MUSIS satellite will be acquired. This is a space based imagery intelligence asset. CERES will deliver national, space-based electronic intelligence. 

- An electronic intelligence package for use on MQ-9 Reaper will be acquired. 12 Reaper remain planned, and deliveries are underway.
On Monday 18 may, France also signed a MOU with France and Germany for the cooperative study and development of an european MALE UAV for the 2020s, that will be the Reaper's replacement. This follows the falling apart of the UK - FR TELEMOS project. Ever since, the UK has been silent, and to this day it remains uncertain how the UK plans to move on and still deliver a UAV for the SCAVENGER requirement, which is also supposed to mitigate the loss of Sentinel R1 and Shadow R1 (pushed back to 2018, but still planned). RAF MQ-9 Reaper themselves have a funding line out to 2019, but the way ahead is uncertain. Answers on this vital requirement will be needed soon.

- 2 of the existing 14 C-130H will be fitted with a weapons capability to be employed in special forces support. 

French armed forces have made it clear that they want to keep a number of C-130s for their needs, arming them as well. Will UK special forces manage to get the MOD and government to listen to their well known, identical wish?


- France will "study", with a decision to be taken by year's end, whether to procure 4 additional C-130s, two of which would be equipped as tankers, in order to provide tactical air refuelling to the Army and Air Force's Special Forces Caracal helicopters. This is due to the delays with A400M, which reportedly include difficulties with the helicopter AAR capability. 

- Deliveries of the new A-330 MRTT "Phènix" will be accelerated. All should be delivered between 2018 and 2025. 

Phènix: what the RAF's own Voyager could and should have been, but isn't.

- 25 new generation targeting pods (the new TALIOS) will be procured in addition to 45 which were already planned. 

- The first batch of 60 SCALP cruise missiles renewed and life-extended is expected in delivery during 2019. UK and France were collaborating on a project for upgrading and life extending the SCALP / Storm Shadow. This might imply that the RAF will start to get upgraded missiles in the same years, but we don't really know. 

- In 2017, design of a successor to the MICA air to air missile will  begin. 

- A GEOINT deployable capability will be procured under the GEODE 4D project. There might be an export chance here for the system the UK has recently developed and put into service, the TIGAS.

- In 2019, the Army will seek to replace the EBG, Engine Blindè du Genie, the combat engineer tractor. France has been looking into (and trialing) the british Terrier as a candidate solution, and while the production line in the UK has shut down, BAE has mothballed the machinery in order to be able to re-open an assembly line, eventually abroad. Terrier thus remains a very likely candidate. 

- The navy will acquire a 4th B2M patrol vessel. Actually, news released since are that this fourth vessel will be a B3M: Bâtiment Multi-Mission Mutualisé. This is due to the ship being destined to be shared between the military, which will employ it for patrolling French Southern and Antarctic Lands, and the polar research institute Paul-Émile Victor. The B3M will be based in La Reunion, and will replace the patrol vessel Albatros (which will be decommissioned within days) and the ship L'Astrolabe, which supplies the Dumont d'Urville base in Antarctica. 
The previous 3 B2M vessels are replacements for the BATRAL light transport ships which for years have flown the flag in the french waters overseas. The first B2M will be based in New Caledonia, the second in the french Polynesia and the third in the West Indies. 

France is also procuring two light patrol vessels specifically designed to serve in Guyana. Having very limited draft, they will be able to push up into rivers. The Patrouilleurs Légers Guyanais were ordered back in december.
By 2020, the french navy will thus have 4 B2M/B3M ships and 2 PLGs covering overseas committments, and 7 old A-69 vessels, plus another 6 legacy patrol vessels of various kinds. The A-69 and other patrol vessels will be replaced under the BATSIMAR project expected to start in 2020. 
6 surveillance frigates based in overseas territories also remain in force. Today this is the Floreal class, but a replacement will be needed later. 

- The FREMM frigates are the losers. It is official at this point that the french navy will receive only 8, two of which configured for Air Defence (FREDA variant). 6 ASW vessels will be delivered by 2019 - 2020, despite the selling of Normandie to Egypt: building times will be speeded up. In 2021 and 2022 the two FREDA will be delivered. 
From 2023, France now plans to be launching a new design frigate, the FTI, frégates de taille intermédiaire, the design of which is not yet known. There is a possibility that it will build upon the new italian PPA design, with some discussions having reportedly already taken place. 
The target of 15 "first rank" warships remains unchanged. The tally is to include 4 anti-air defence warships and 11 frigates. Currently, the total is made up by the 2 Forbin / HORIZON class AAW destroyers, 2 F70 AAW legacy ships, old F70 ASW frigates and FREMM ships entering in service. 
The 5 La Fayette frigates will be upgraded and fitted with sonar to help keep the total at 15 as the old F70 ASW ships are withdrawn from service. 
The two FREDA will replace the F70 AAW in 2021 and 2022. 
Then, from 2023, the La Fayette themselves will be replaced by the new FTIs. 

- From 2021, SLAMF (Système de Lutte Anti Mines – Futur) is supposed to deliver new solutions to the MCM requirement. Eventually, the minesweepers will be replaced by 8 systems of unmanned surface and underwater vehicles, deployable at sea with four large motherships.
Apparently, and very surprisingly, five separate ships are also planned as bases for clearance divers, according to the MOD's document. 
The development of the unmanned vehicles and general architecture for the umanned, stand-off clearance of minefields at sea is a collaborative project with the UK, with several demonstration contracts awarded in the last few months. The UK's MHC solution will use many of the same drones. 

- Funding is provided for 4 Bâtiment de Soutien et d'Assistance Hauturier (BSAH), ocean-going tugs and support ships. 

- From 2017, France will be ordering a new assault rifle to replace FAMAS 

- For the future replacement of the C-160 Gabriel electronic warfare aircraft, France plans the procurement of Charge Universelle de Guerre Electronique (CUGE), a modular payload which will be embarked on cargo aircraft (A400, or maybe C-130 or even the smaller C-235) as necessary, removing the need for a dedicate, specific platform. 

- France will be in the market for a new solution for the training of jet pilots under the Formation Moderniseè et Entrainement Diffèrenciè des Equipages de Chasse. There is a possibility that France will collaborate with Italy, maybe even sending pilots to the 61st Wing training school at Lecce Galatina, Italy, for training.  




Other plans remain substantially unchanged from earlier versions. The army will still want to procure a tactical UAV, and the Watchkeeper is a leading candidate. 

In 2020, the Navy will seek to launch FLOTLOG, the programme for the acquisition of 3 new supply ships for the logistics of the fleet. 

Acquisition of all 630 VBCI will be followed by projects of modernisation, including the addition of turret-mounted missile launchers and enhanced networking within the SCORPION project. 
The Army plans to acquire 2080 VBMR, including 358 in "Light", 4x4 variant to replace the VAB.
248 EBRC Scouts will replace the AMX 10RC and Sagaie ERC 90.   
At a later date, 1470 VBAE (véhicules blindés d’aide à l’engagement) are expected to be procured to replace the VBL light armoured cars. 
200 Leclerc MBTs and 18 Leclerc recovery vehicles are under contract for modernization and life extension. Artillery is going to be a bit short of guns if there will not be additional purchases of CAESAR truck-mounted 155/52 howitzers. Currently, 77 are on order, but as the tracked self-propelled guns retire, more would be needed. 
13 launchers are being upgraded to GMLRS. 

The Air Force continues to plan for a long-term figure of 185 combat jets, between Rafale and modernized Mirage 2000.  
The Navy will add 40 Rafale M of its own, as the last Super Etendard Modernisee is withdrawn by 2017.

The nuclear deterrent will continue to be based on some 300 warheads. Three full sets of 16 M-51 submarine launched missiles will be maintained for the fleet of 4 SSBN; and the air force maintains a stock of some 54 ASMP-A missiles.  

The fleet of maritime patrol aircraft will shrink to 15 upgraded ATL-2 over the long period. These will continue to be complemented by a further 4 ATL-2 used for surface surveillance, as well as 4 Falcon 50M, 5 Falcon 200 Guardian and a further 4 Falcon 50 due to be converted and fitted with SAR radar. 

The main helicopter of the Navy will be the NH-90 NFH Cayman, 27 of which are on order, along with 14 palletized ASW kits with sonar Flash to employ on them when and where necessary. These will still be complemented by some 40 more light helicopters (Alouette, Panther, Dauphin) in 2020.  



Sunday, April 15, 2012

CVF and JCA: why i'd go CATOBAR

 
F35B and F35C: the airplane situation

Of immense interest is the 2011 Department of Defence Annual Report for the Office of the Director, Operational Test & Evaluation which gives us an up to date major picture of the current F35 development and testing situation. In the detail, it tells of everything that still does not work with the F35, and details the progress of the program in 2011. 

It is very useful to draw some well-informed conclusions, and contains some interesting data. For example, it emerges that: 

- F35A is 11% behind schedule with its test and validation campaign
- F35B is 9% behind schedule
- F35C is 32% ahead of schedule

We must, of course, look at the 32% ahead of schedule data with the awareness that the C is the variant who entered trials last. The other two variants are ahead of the F35C with their programs of development, testing and validation as they are closer to entering active service. For example the B already went at sea, while the C won't go on an aircraft carrier until next year.
However, A and B are lagging considerably in terms of test points cleared, while the F35C has cleared 32% more test points than planned, which is very reassuring. Having started later also means that more corrections have been incorporated into the C at build, thanks to discoveries made on the other two variants.

The planning, updated to December 2011, is for the three variants to complete their development and testing with many more flights. In each flight, a number of tests are run, in order to validate long lists of requirements. Each airframe requirement makes for 1 or several "test points". As of December 2011, maturity of the F35C was 1002 test flights away, with 12.442 test points yet to clear.
 
The A still has 827 flights and 10.257 test points to go.
 
The B 1,437 flights and 15.045 points.


These values of course change rather frequently when a change proves necessary and needs to be flown and trialed, adding new flights and points to clear to the count, but they are indicative of the current plan. 

Regarding the F35B trials at sea on USS Wasp, which were presented by the STOVL prophets as having proven that the B has "no issues" and that the jet blast hazard claims were "nonsense" and that everything actually works perfectly well, well, the reality is actually a bit different. The F35B jet blast does not hole the deck as someone had (rather extremely) prophetized, no, but a jet blast issues exists and the trials at sea only confirmed it. A 75 feet danger radius is reported. 

Jet blast from the F-35Bs is expected to produce unsafe forces on flight deck personnel up to 75 feet from the short take-off line.
This is going to make another serious dent, along with Ship  Borne Rolling Vertical Landing, in the flaunted advantages of STOVL when conducting simultaneous jet and helicopter operations on deck, which some describe as indispansable for the success of Carrier Enabled Power Projection. 
With jet blast hazard and landing runs on the deck, the differences between F35B and F35C in deck usage during ops are getting smaller and smaller.  

Among the F35B issues, is the cracking of a wing carry-through bulkhead cracked before 2,000 hours of airframe life. The required airframe lifetime is 8,000 hours. Repair of the bulkhead on the test article was completed in November 2011, and F-35B durability testing should have restarted in January 2012.

Following the bulkhead crack in the F-35B test article, analysis verified the existence of numerous other life‑limited parts on all three variants. The program began developing plans to correct these deficiencies in existing aircraft by repair/modifications, and designing changes to the production process. The most significant of these in terms of complexity, aircraft downtime, and difficulty of the modification required for existing aircraft is the forward wing root rib on the F-35A [which failed after some 3000 hours] and F-35B aircraft.

The F35C's own durability testing are due to start in the next while, if it hasn't already. By August last year the C had completed all of its structural test points, including drop tests to simulate rough carrier landing stress on the airframe. 

The F35B has had  a large number of parts re-designed and replaced and corrected, and the reports notes that, so far, there's no plan in place for rolling in the modifications in production airplanes. The report acknowledges: 

The program has not completed the final re-designs and plans to correct deficiencies through modifications of F-35B production aircraft intended for the fleet, which cannot be monitored in-flight because these aircraft are not instrumented. Production aircraft will be restricted from STOVL-mode flight operations until Service airworthiness authorities grant a flight clearance. A significant amount of flight test and development of system maturity of the final STOVL-mode door and propulsion system designs remains to be accomplished. A system mature enough for unmonitored STOVL-mode flight may be needed as early as late 2012 to coincide with the delivery of lot 4 F-35B aircraft to the Marine Corps at Yuma, Arizona. If testing of the changes is not complete and needed modifications are not installed by late 2012, aircraft at Yuma will fly in CTOL‑mode only.

The full extent of issues so far detected in the airframe doors and STOVL propulsion assembly is reported in a table, and makes for rather depressing reading, with some of the solutions in development already planned not to be ready before LRIP 7 while other solutions have yet to be determined, tested, and planned for adoption on production standard airplanes. 

The table of the F35B propulsion and door issues, as presented in the report.
There is also serious problems with overheating of the clutch that can prevent the STOVL mode to be angaged (how do you land at that point if your only runway is the carrier, or is just too short for a CTOL landing???) for which a real solution does not yet exists, and the driveshaft has to be redesigned. 

Besides, the F35B has a margin for growth of sole 230 pounds before it breaks its not-to-exceed weight planned for 2015. An additional 142 pounds might be secured by a greater descent rate to touchdown, but it is far from certain, and even so that means just 372 pounds of weight growth margin available, before the deadly line is crossed, with several years of testing and development yet to go, and no military service at all done. 
Talk about constrained airframes... 

The report notes: 

This additional weight [the 142 additional pounds of margin, to 372 total] increases the margin to 1.2 percent of current weight and allows for 0.36 percent weight growth
per year. Managing weight growth with such tight margins for the balance of SDD will be a significant challenge, especially with over 70 percent of the scheduled F-35B flight sciences test flights remaining to be accomplished in the next 60 months. For comparison, weight growth on the F/A-18 E/F was approximately 0.69 percent per year for  the first 42 months following first flight.

Again, undesirable wing roll-off, airframe buffet, and sideslip occurred in transonic flight regimes, and handling characteristics as a consequence do not meet requirements. It is likely that no more changes will be made to the plane, and it will be the requirements that are reviewed and reduced, in order for the plane to "meet" them!

The final word on the F35B can be identified in this passage: 

In October 2011, the program successfully conducted initial amphibious ship trials with STOVL aircraft in accordance with the new, restructured plan for 2011; however, significant work and flight tests remain to verify and incorporate modifications
to STOVL aircraft required to correct known STOVL deficiencies and prepare the system for operational use.

Regarding the F35C, the report says: 

F-35C Flight Sciences
• As F-35C flight sciences focused on preparation for and execution of carrier launch and landing testing at Lakehurst, a limited amount of other envelope expansion occurred in 2011.
The F-35C flight sciences test points accomplished thus far are approximately 15 percent of the total expected in SDD.

• The lack of available flight envelope in the transonic regime currently constrains testing of F-35C aircraft handling qualities. In limited testing using flight control software that
benefitted from F-35A and F-35B testing, the F-35C aircraft performance in the transonic flight regime demonstrated the predicted intensity of uncommanded rolls but higher buffet
levels. The F-35C aircraft was expected to have the greatest challenge of the three variants in the transonic flight regime, which led to the decision to incorporate structural provisions for the installation of external spoilers in one test aircraft.
(Buffet is a problem of all three variants, it seems, and indeed a common problem in american naval jets, since the F-18 notoriously had this kind of issues too!) 
• The carrier launch and landing testing at Lakehurst provided valuable lessons regarding the impacts of these dynamic environments on the aircraft early in the testing.
Corrections and regression testing are needed as a result of the discoveries listed below. The program is also working to correct other performance problems such as excessive
nose gear oscillations during taxi, excessive landing gear retraction times, and overheating of the electro-hydrostatic actuator systems that power the flight controls. The program will subsequently evaluate the need for modifications of production aircraft for these items.
• Discoveries included:
-- Flight test aircraft could not engage the arrestment cable
during tests at the Lakehurst, New Jersey, test facility. The
tail-hook point is undergoing a redesign and the hold-down
damper mechanism requires modifications to enable
successful arrestments on the carrier. Resolution of these
deficiencies is needed for testing to support F-35C ship
trials in late 2013.
-- Hold-back bar and torque arm components, which keep the
F-35C aircraft from moving forward when tensioned on the
catapult at full power, require a redesign due to the use of
incorrect design load factors. Actual loads are greater than
predicted. The impact of these greater‑than‑predicted loads
on strength and fatigue characteristics is under analysis by
the program.
-- Loss of inertial navigation and GPS inputs to pilot displays
occurred during a catapult launch. Root cause analysis was
in progress at the time of this report.
-- The test team conducted initial testing in the transonic
flight regimes with one version of air vehicle software on
aircraft CF-2. Problems similar to the other variants were
observed, such as excessive buffeting and roll-off, at times
making the helmet-mounted displays unreadable.
-- Higher than predicted temperatures exist in the
electro‑hydrostatic actuator system during flight testing
of the aircraft in a landing configuration. This component
provides the force to move control surfaces.

In addition, the F35C acceleration is inferior to the hoped value.

The F35B is still far from its maturity, with several thousand test points more than the other variants to clear and with a huge variety of very serious issues to fix and with a significant amount of changes and redesigning already having taken place.
The F35C has its problems too, but is in a remarkably better shape and, save for the arrestor hook issue, which is said to be due for fixing in the next few months, has not revealed problems potentially show-stopping. The B's extremely low growth margin, with associated Bring Back weight issues, is instead a very serious menace to its viability as embarked plane for CVF. 



CATOBAR reasons and issues 

Reasons:  

- Maximum interoperability. Rafale, F-18, F-35C but also STOVL F35B can work from a big CATOBAR deck. The opposite is not true. 

- Future proof. Any kind of naval drone which will be developed in the coming years will be able to operate from the carrier. We will also be able to benefit from research and development done by the US Navy, and benefit of their support and investments into EMALS, AAG, and compatible platforms. 

- Compatible with future adoptions of better COD, AEW and tanker platforms. 

- Maximum military performances. It makes it possible to use the most capable embarked airplanes, and it fits into the operations of the two main allies of the UK. 


Issues:  

- Cost. EMALS and AAG add up-front cost to the carriers, and come with a personnel and training penalty. 


I've tried to quantify the extent of the training penalty connected to CATOBAR ops, but it is not easy at all.
I've discovered that a Sea Harrier FA2 pilot was a Naval All Weather Fighter Pilot after 100 day and 80 night landings on deck, but i've been unable to find a figure for the number of day and night landings necessary to re-certify for ops when the pilots are assigned to active service on the carrier.

On the other side of the barricade, i don't have a figure for the number of landings required for initial pilot certification, but i know that France's carrier pilots re-certify for carrier ops currency by making 6 daytime arrested landings and 4 night time arrested landings. A direct comparison in this latest value would be invaluable in assessing the feasibility of having RAF pilots, initially certified to CATOBAR ops, getting current again quickly to reiforce the naval strike wing embarked on the carrier.

The STOVL prophets say that re-certification with the Harrier required far fewer landings, and was much more readily achievable. They say that with CATOBAR, it wouldn't be possible to have one naval squadron plus 2/3 land squadrons able to reinforce the embarked complement in case of crisis, but we'd need a CATOBAR cadre of at least 3 naval squadrons.
Assuming they are right and it is true,  my reply is: that's how things should have always been.

While there's several clear and rationale reasons for having a naval fixed wing element [provide air defence for the fleet and independent, full spectrum air power even when airbases are not available], which brings to the table some very unique capabilities, i believe the rationale for a separate land based fleet of "deep penetrating" strike planes to replace Tornado has never been weaker. And in many ways it is a duplicate of the carrier strike fleet.

The RAF's JCA plan so far has been to get a land fleet of planes, capable to, at a stretch, migrate on the carrier when necessary. But considered the difficulties of getting land pilots to operate from ships, it will always make more operational sense to have naval pilots instead, who can readily work from land bases if the situation calls for it.
It is much easier to put a naval squadron ashore than a land squadron at sea, it is undeniable.

If CATOBAR requires a greater focus on naval operations, so be it, i say. France does not do bad at all with its own naval aviation, considering that they deployed a sizeable and capable force at sea for Libya ops, even though Charles De Gaulle was back from four months of ops over Afghanistan by less than one month.
They did especially well considering that their naval air force at the time had a single Rafale squadron, 12F, with an establishment of 15 airplanes, plus two Super Etendard squadrons, 11F and 17F.
Now, finally, 11F is converting to Rafale as part of the progressive retirement of the Super Etendard. The naval fixed wing complement is of course completed by 4F squadron, with the 3 E2C Hawkeye. Numerically, if the UK is really to order 50 F35s, the numbers are similar, as France has so far ordered 48 Rafale M, and has lost 3 to accidents, giving them a fleet of potentially just 45 airframes, even if once they were hoping for 60.

Looking at France's small but efficient CATOBAR naval aviation, i say that Britain could no doubt at least match it, standing up three naval-focused, if not naval-owned, squadrons of 14 F35C each (as 2 would normally be roled as Buddy-Buddy tankers).
France trains its naval pilots in the US, where they fly and "trap" on the T-45 Goshawk. When they come back, as few as 12 hours on the Rafale simulator are sufficient to achieve conversion to type. Much like with the F35, there is not a (naval) two-seat Rafale trainer. Differently from the F35, which pretty much never envisaged it, the Rafale N was planned (naval two-seat) and the airforce has the two-seat B variant. From late 2010, the Armee de l'Air has formed a large Rafale training squadron (2/92 Aquitanie) which offers some 4 slots a year for naval pilots to exploit some hours on the two-seat Rafale for combat system advanced training.
The RAF and RN hope to cover this requirement for the F35 with the Hawk T2 and with the simulators.  
On land, carrier landing practice is done by french pilots without a carrier-shaped runway with wires: a standard runway, with a marked "square" area the same size of the one that on a carrier would sport the wires is sufficient for good practice prior to embarkation on the aircraft carrier.

Keep in mind that the F35 promises to come with the best and most realistic simulators ever developed, and much of the training is to be done on sims, so matching what France does with the Rafales is the minimum i expect.

I do not think CATOBAR represents such an insurmontable challenge, if the decision is eventually taken to go ahead with it.
The problem is financing the conversion of the two carriers, essentially. And accepting that naval aviation is a serious trade, that should not be half-assed with part-time solutions.